Implements web view for presenting Auth web content on iOS 7 and 8. (#253)

Also (hopefully) fixes thread safety issues in presenting Auth web content.

12 files changed, 466 insertions, 84 deletions

diff --git a/Example/Auth/Tests/FIRAuthURLPresenterTests.m b/Example/Auth/Tests/FIRAuthURLPresenterTests.m
index 5d42e5f..fcc64e9 100644
--- a/Example/Auth/Tests/FIRAuthURLPresenterTests.m
+++ b/Example/Auth/Tests/FIRAuthURLPresenterTests.m
@@ -21,6 +21,7 @@
 
 #import "FIRAuthUIDelegate.h"
 #import "FIRAuthURLPresenter.h"
+#import "FIRAuthWebViewController.h"
 
 /** @var kExpectationTimeout
     @brief The maximum time waiting for expectations to fulfill.
@@ -61,7 +62,6 @@ static NSTimeInterval kExpectationTimeout = 1;
  */
 - (void)testFIRAuthURLPresenterUsingDefaultUIDelegate:(BOOL)usesDefaultUIDelegate {
   id mockUIDelegate = OCMProtocolMock(@protocol(FIRAuthUIDelegate));
-  id mockUIApplication = OCMPartialMock([UIApplication sharedApplication]);
   NSURL *presenterURL = [NSURL URLWithString:@"https://presenter.url"];
   FIRAuthURLPresenter *presenter = [[FIRAuthURLPresenter alloc] init];
 
@@ -70,68 +70,70 @@ static NSTimeInterval kExpectationTimeout = 1;
     OCMStub(ClassMethod([mockDefaultUIDelegateClass defaultUIDelegate])).andReturn(mockUIDelegate);
   }
 
-  XCTestExpectation *callbackMatcherExpectation =
-      [self expectationWithDescription:@"callbackMatcher callback"];
+  __block XCTestExpectation *callbackMatcherExpectation;
   FIRAuthURLCallbackMatcher callbackMatcher = ^BOOL(NSURL *_Nonnull callbackURL) {
+    XCTAssertNotNil(callbackMatcherExpectation);
     XCTAssertEqualObjects(callbackURL, presenterURL);
     [callbackMatcherExpectation fulfill];
     return YES;
   };
 
-  XCTestExpectation *completionBlockExpectation =
-      [self expectationWithDescription:@"completion callback"];
+  __block XCTestExpectation *completionBlockExpectation;
   FIRAuthURLPresentationCompletion completionBlock = ^(NSURL *_Nullable callbackURL,
                                                        NSError *_Nullable error) {
+    XCTAssertNotNil(completionBlockExpectation);
     XCTAssertEqualObjects(callbackURL, presenterURL);
     XCTAssertNil(error);
     [completionBlockExpectation fulfill];
   };
 
-  if ([SFSafariViewController class]) {
-    id presenterArg = [OCMArg isKindOfClass:[SFSafariViewController class]];
-    OCMExpect([mockUIDelegate presentViewController:presenterArg
-                                           animated:YES
-                                         completion:nil]).andDo(^(NSInvocation *invocation) {
-      __unsafe_unretained id unretainedArgument;
-      // Indices 0 and 1 indicate the hidden arguments self and _cmd.
-      // `presentViewController` is at index 2.
-      [invocation getArgument:&unretainedArgument atIndex:2];
-
-      SFSafariViewController *viewController = unretainedArgument;
-      XCTAssertEqual(viewController.delegate, presenter);
+  XCTestExpectation *UIPresentationExpectation = [self expectationWithDescription:@"present UI"];
+  OCMExpect([mockUIDelegate presentViewController:[OCMArg any]
+                                         animated:YES
+                                       completion:nil]).andDo(^(NSInvocation *invocation) {
+    XCTAssertTrue([NSThread isMainThread]);
+    __unsafe_unretained id unretainedArgument;
+    // Indices 0 and 1 indicate the hidden arguments self and _cmd.
+    // `presentViewController` is at index 2.
+    [invocation getArgument:&unretainedArgument atIndex:2];
+
+    id presentViewController = unretainedArgument;
+    if ([SFSafariViewController class]) {
+      SFSafariViewController *viewController = presentViewController;
       XCTAssertTrue([viewController isKindOfClass:[SFSafariViewController class]]);
-    });
-  } else {
-    id mockUIApplicationClass = OCMClassMock([UIApplication class]);
-    OCMStub(ClassMethod([mockUIApplicationClass sharedApplication])).andReturn(mockUIApplication);
-    OCMExpect([mockUIApplication openURL:OCMOCK_ANY]).andDo(^(NSInvocation *invocation) {
-      __unsafe_unretained id unretainedArgument;
-      // Indices 0 and 1 indicate the hidden arguments self and _cmd.
-      // `openURL` is at index 2.
-      [invocation getArgument:&unretainedArgument atIndex:2];
-      XCTAssertEqualObjects(presenterURL, unretainedArgument);
-    });
-  }
+      XCTAssertEqual(viewController.delegate, presenter);
+    } else {
+      UINavigationController *navigationController = presentViewController;
+      XCTAssertTrue([navigationController isKindOfClass:[UINavigationController class]]);
+      FIRAuthWebViewController *webViewController =
+          navigationController.viewControllers.firstObject;
+      XCTAssertTrue([webViewController isKindOfClass:[FIRAuthWebViewController class]]);
+    }
+    [UIPresentationExpectation fulfill];
+  });
 
   // Present the content.
   [presenter presentURL:presenterURL
              UIDelegate:usesDefaultUIDelegate ? nil : mockUIDelegate
         callbackMatcher:callbackMatcher
              completion:completionBlock];
+  [self waitForExpectationsWithTimeout:kExpectationTimeout handler:nil];
   OCMVerifyAll(mockUIDelegate);
-  OCMVerifyAll(mockUIApplication);
-  if ([SFSafariViewController class]) {
-    OCMExpect([mockUIDelegate dismissViewControllerAnimated:OCMOCK_ANY
-                                                 completion:OCMOCK_ANY])
-        .andDo(^(NSInvocation *invocation) {
-      __unsafe_unretained id unretainedArgument;
-      // Indices 0 and 1 indicate the hidden arguments self and _cmd.
-      // `completion` is at index 3.
-      [invocation getArgument:&unretainedArgument atIndex:3];
-      void (^finishBlock)() = unretainedArgument;
-      finishBlock();
-    });
-  }
+
+  // Pretend dismissing view controller.
+  OCMExpect([mockUIDelegate dismissViewControllerAnimated:OCMOCK_ANY
+                                               completion:OCMOCK_ANY])
+      .andDo(^(NSInvocation *invocation) {
+    XCTAssertTrue([NSThread isMainThread]);
+    __unsafe_unretained id unretainedArgument;
+    // Indices 0 and 1 indicate the hidden arguments self and _cmd.
+    // `completion` is at index 3.
+    [invocation getArgument:&unretainedArgument atIndex:3];
+    void (^completion)() = unretainedArgument;
+    dispatch_async(dispatch_get_main_queue(), completion);
+  });
+  completionBlockExpectation = [self expectationWithDescription:@"completion callback"];
+  callbackMatcherExpectation = [self expectationWithDescription:@"callbackMatcher callback"];
 
   // Close the presented content.
   XCTAssertTrue([presenter canHandleURL:presenterURL]);
diff --git a/Example/Auth/Tests/FIRUserTests.m b/Example/Auth/Tests/FIRUserTests.m
index 64051a3..a0a2644 100644
--- a/Example/Auth/Tests/FIRUserTests.m
+++ b/Example/Auth/Tests/FIRUserTests.m
@@ -1302,6 +1302,7 @@ static const NSTimeInterval kExpectationTimeout = 1;
                                             completion:^(FIRAuthDataResult *_Nullable
                                                             linkAuthResult,
                                                          NSError *_Nullable error) {
+      XCTAssertTrue([NSThread isMainThread]);
       XCTAssertNil(linkAuthResult);
       XCTAssertEqual(error.code, FIRAuthErrorCodeTooManyRequests);
       [expectation fulfill];
diff --git a/Firebase/Auth/FirebaseAuth.podspec b/Firebase/Auth/FirebaseAuth.podspec
index ad4c54f..57b8a73 100644
--- a/Firebase/Auth/FirebaseAuth.podspec
+++ b/Firebase/Auth/FirebaseAuth.podspec
@@ -33,6 +33,8 @@ Simplify your iOS development, grow your user base, and monetize more effectivel
     'Source/**/FIRAuthDefaultUIDelegate.[mh]',
     'Source/**/FIRAuthUIDelegate.h',
     'Source/**/FIRAuthURLPresenter.[mh]',
+    'Source/**/FIRAuthWebView.[mh]',
+    'Source/**/FIRAuthWebViewController.[mh]',
     'Source/**/FIRPhoneAuthCredential.[mh]',
     'Source/**/FIRPhoneAuthProvider.[mh]'
   s.public_header_files = 'Source/Public/*.h'
diff --git a/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m b/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
index 32b5da0..7587f1b 100644
--- a/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
+++ b/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
@@ -146,15 +146,16 @@ NSString *const kReCAPTCHAURLStringFormat = @"https://%@/__/auth/handler?%@";
           callBackOnMainThread(nil, error);
           return;
         }
+        FIRAuthURLCallbackMatcher callbackMatcher = ^BOOL(NSURL *_Nullable callbackURL) {
+          return [self isVerifyAppURL:callbackURL];
+        };
         [_auth.authURLPresenter presentURL:reCAPTCHAURL
                                 UIDelegate:UIDelegate
-                           callbackMatcher:^BOOL(NSURL * _Nullable callbackURL) {
-                             return [self isVerifyAppURL:callbackURL];
-                           }
+                           callbackMatcher:callbackMatcher
                                 completion:^(NSURL *_Nullable callbackURL,
                                              NSError *_Nullable error) {
           if (error) {
-            completion(nil, error);
+            callBackOnMainThread(nil, error);
             return;
           }
           NSError *reCAPTCHAError;
diff --git a/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.h b/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.h
new file mode 100644
index 0000000..f0e5d80
--- /dev/null
+++ b/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "FIRAuthUIDelegate.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FIRAuthDefaultUIDelegate : NSObject <FIRAuthUIDelegate>
+
+/** @fn defaultUIDelegate
+    @brief Unavailable. Please use @c +defaultUIDelegate:
+ */
+- (instancetype)init NS_UNAVAILABLE;
+
+/** @fn defaultUIDelegate
+    @brief Returns a default FIRAuthUIDelegate object.
+    @return The default FIRAuthUIDelegate object.
+ */
++ (id<FIRAuthUIDelegate>)defaultUIDelegate;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.m b/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.m
index 118b73c..a00d0e9 100644
--- a/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.m
+++ b/Firebase/Auth/Source/FIRAuthDefaultUIDelegate.m
@@ -14,24 +14,20 @@
  * limitations under the License.
  */
 
-#import <Foundation/Foundation.h>
-
-#import "FIRAuthUIDelegate.h"
+#import "FIRAuthDefaultUIDelegate.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FIRAuthDefaultUIDelegate : NSObject <FIRAuthUIDelegate>
-/** @fn defaultUIDelegate
-    @brief Unavailable. Please use initWithViewController:
- */
-- (instancetype)init NS_UNAVAILABLE;
+@interface FIRAuthDefaultUIDelegate ()
 
 /** @fn initWithViewController:
     @brief Initializes the instance with a view controller.
-    @param viewController The view controller as the presenting view controller in @c GOIUIDelegate.
+    @param viewController The view controller as the presenting view controller in @c
+        FIRAuthUIDelegate.
     @return The initialized instance.
  */
 - (instancetype)initWithViewController:(UIViewController *)viewController NS_DESIGNATED_INITIALIZER;
+
 @end
 
 @implementation FIRAuthDefaultUIDelegate {
diff --git a/Firebase/Auth/Source/FIRAuthURLPresenter.m b/Firebase/Auth/Source/FIRAuthURLPresenter.m
index 722326c..d923c8a 100644
--- a/Firebase/Auth/Source/FIRAuthURLPresenter.m
+++ b/Firebase/Auth/Source/FIRAuthURLPresenter.m
@@ -18,20 +18,15 @@
 
 #import <SafariServices/SafariServices.h>
 
+#import "FIRAuthDefaultUIDelegate.h"
 #import "FIRAuthErrorUtils.h"
+#import "FIRAuthGlobalWorkQueue.h"
 #import "FIRAuthUIDelegate.h"
+#import "FIRAuthWebViewController.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FIRAuthDefaultUIDelegate : NSObject <FIRAuthUIDelegate>
-/** @fn defaultUIDelegate
-    @brief Returns a default FIRAuthUIDelegate object.
-    @return The default FIRAuthUIDelegate object.
- */
-+ (id<FIRAuthUIDelegate>)defaultUIDelegate;
-@end
-
-@interface FIRAuthURLPresenter () <SFSafariViewControllerDelegate>
+@interface FIRAuthURLPresenter () <SFSafariViewControllerDelegate, FIRAuthWebViewDelegate>
 @end
 
 @implementation FIRAuthURLPresenter {
@@ -50,6 +45,11 @@ NS_ASSUME_NONNULL_BEGIN
    */
   SFSafariViewController *_Nullable _safariViewController;
 
+  /** @var _webViewController
+      @brief The FIRAuthWebViewController used for the current presentation, if any.
+   */
+  FIRAuthWebViewController *_Nullable _webViewController;
+
   /** @var _UIDelegate
       @brief The UIDelegate used to present the SFSafariViewController.
    */
@@ -74,17 +74,20 @@ NS_ASSUME_NONNULL_BEGIN
   _isPresenting = YES;
   _callbackMatcher = callbackMatcher;
   _completion = completion;
-  _UIDelegate = UIDelegate ?: [FIRAuthDefaultUIDelegate defaultUIDelegate];
-  if ([SFSafariViewController class]) {
-    SFSafariViewController *safariViewController = [[SFSafariViewController alloc] initWithURL:URL];
-    _safariViewController = safariViewController;
-    _safariViewController.delegate = self;
-    [_UIDelegate presentViewController:safariViewController animated:YES completion:nil];
-    return;
-  } else {
-    // TODO: Use web view instead.
-    [[UIApplication sharedApplication] openURL:URL];
-  }
+  dispatch_async(dispatch_get_main_queue(), ^() {
+    _UIDelegate = UIDelegate ?: [FIRAuthDefaultUIDelegate defaultUIDelegate];
+    if ([SFSafariViewController class]) {
+      _safariViewController = [[SFSafariViewController alloc] initWithURL:URL];
+      _safariViewController.delegate = self;
+      [_UIDelegate presentViewController:_safariViewController animated:YES completion:nil];
+      return;
+    } else {
+      _webViewController = [[FIRAuthWebViewController alloc] initWithURL:URL delegate:self];
+      UINavigationController *navController =
+          [[UINavigationController alloc] initWithRootViewController:_webViewController];
+      [_UIDelegate presentViewController:navController animated:YES completion:nil];
+    }
+  });
 }
 
 - (BOOL)canHandleURL:(NSURL *)URL {
@@ -98,13 +101,45 @@ NS_ASSUME_NONNULL_BEGIN
 #pragma mark - SFSafariViewControllerDelegate
 
 - (void)safariViewControllerDidFinish:(SFSafariViewController *)controller {
-  if (controller == _safariViewController) {
-    _safariViewController = nil;
-    //TODO:Ensure that the SFSafariViewController is actually removed from the screen before
-    //invoking finishPresentationWithURL:error:
-    [self finishPresentationWithURL:nil
-                              error:[FIRAuthErrorUtils webContextCancelledErrorWithMessage:nil]];
-  }
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^() {
+    if (controller == _safariViewController) {
+      _safariViewController = nil;
+      //TODO:Ensure that the SFSafariViewController is actually removed from the screen before
+      //invoking finishPresentationWithURL:error:
+      [self finishPresentationWithURL:nil
+                                error:[FIRAuthErrorUtils webContextCancelledErrorWithMessage:nil]];
+    }
+  });
+}
+
+#pragma mark - FIRAuthwebViewControllerDelegate
+
+- (BOOL)webViewController:(FIRAuthWebViewController *)webViewController canHandleURL:(NSURL *)URL {
+  __block BOOL result = NO;
+  dispatch_sync(FIRAuthGlobalWorkQueue(), ^() {
+    if (webViewController == _webViewController) {
+      result = [self canHandleURL:URL];
+    }
+  });
+  return result;
+}
+
+- (void)webViewControllerDidCancel:(FIRAuthWebViewController *)webViewController {
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^() {
+    if (webViewController == _webViewController) {
+      [self finishPresentationWithURL:nil
+                                error:[FIRAuthErrorUtils webContextCancelledErrorWithMessage:nil]];
+    }
+  });
+}
+
+- (void)webViewController:(FIRAuthWebViewController *)webViewController
+         didFailWithError:(NSError *)error {
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^() {
+    if (webViewController == _webViewController) {
+      [self finishPresentationWithURL:nil error:error];
+    }
+  });
 }
 
 #pragma mark - Private methods
@@ -127,8 +162,14 @@ NS_ASSUME_NONNULL_BEGIN
   };
   SFSafariViewController *safariViewController = _safariViewController;
   _safariViewController = nil;
-  if (safariViewController) {
-    [UIDelegate dismissViewControllerAnimated:YES completion:finishBlock];
+  FIRAuthWebViewController *webViewController = _webViewController;
+  _webViewController = nil;
+  if (safariViewController || webViewController) {
+    dispatch_async(dispatch_get_main_queue(), ^() {
+      [UIDelegate dismissViewControllerAnimated:YES completion:^() {
+        dispatch_async(FIRAuthGlobalWorkQueue(), finishBlock);
+      }];
+    });
   } else {
     finishBlock();
   }
diff --git a/Firebase/Auth/Source/FIRAuthWebView.h b/Firebase/Auth/Source/FIRAuthWebView.h
new file mode 100644
index 0000000..f4a8d1b
--- /dev/null
+++ b/Firebase/Auth/Source/FIRAuthWebView.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <UIKit/UIKit.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FIRAuthWebView : UIView
+
+/** @property webView
+ *  @brief The web view.
+ */
+@property(nonatomic, weak) UIWebView *webView;
+
+/** @property spinner
+ *  @brief The spinner that indicates web view loading.
+ */
+@property(nonatomic, weak) UIActivityIndicatorView *spinner;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/FIRAuthWebView.m b/Firebase/Auth/Source/FIRAuthWebView.m
new file mode 100644
index 0000000..80b90f0
--- /dev/null
+++ b/Firebase/Auth/Source/FIRAuthWebView.m
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "FIRAuthWebView.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@implementation FIRAuthWebView
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  self = [super initWithFrame:frame];
+  if (self) {
+    self.backgroundColor = [UIColor whiteColor];
+    [self initializeSubviews];
+  }
+  return self;
+}
+
+/** @fn initializeSubviews
+    @brief Initializes the subviews of this view.
+ */
+- (void)initializeSubviews {
+  UIWebView *webView = [self createWebView];
+  UIActivityIndicatorView *spinner = [self createSpinner];
+
+  // The order of the following controls z-order.
+  [self addSubview:webView];
+  [self addSubview:spinner];
+
+  [self layoutSubviews];
+  _webView = webView;
+  _spinner = spinner;
+}
+
+- (void)layoutSubviews {
+  CGFloat height = self.bounds.size.height;
+  CGFloat width = self.bounds.size.width;
+  _webView.frame = CGRectMake(0, 0, width, height);
+  _spinner.center = _webView.center;
+}
+
+/** @fn createWebView
+    @brief Creates a web view to be used by this view.
+    @return The newly created web view.
+ */
+- (UIWebView *)createWebView {
+  UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectZero];
+  // Trickery to make the web view not do weird things (like showing a black background when
+  // the prompt in the navigation bar animates changes.)
+  webView.opaque = NO;
+  webView.backgroundColor = [UIColor clearColor];
+  webView.scrollView.opaque = NO;
+  webView.scrollView.backgroundColor = [UIColor clearColor];
+  webView.scrollView.bounces = NO;
+  webView.scrollView.alwaysBounceVertical = NO;
+  webView.scrollView.alwaysBounceHorizontal = NO;
+  return webView;
+}
+
+/** @fn createSpinner
+    @brief Creates a spinner to be used by this view.
+    @return The newly created spinner.
+ */
+- (UIActivityIndicatorView *)createSpinner {
+  UIActivityIndicatorViewStyle spinnerStyle = UIActivityIndicatorViewStyleGray;
+  UIActivityIndicatorView *spinner =
+      [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:spinnerStyle];
+  return spinner;
+}
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/FIRAuthWebViewController.h b/Firebase/Auth/Source/FIRAuthWebViewController.h
new file mode 100644
index 0000000..5c2c042
--- /dev/null
+++ b/Firebase/Auth/Source/FIRAuthWebViewController.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <UIKit/UIKit.h>
+
+@class FIRAuthWebViewController;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@protocol FIRAuthWebViewDelegate <NSObject>
+
+/** @fn webViewController:canHandleURL:
+    @brief Determines if a URL should be handled by the delegate.
+    @param URL The URL to handle.
+    @return Whether the URL could be handled or not.
+ */
+- (BOOL)webViewController:(FIRAuthWebViewController *)webViewController canHandleURL:(NSURL *)URL;
+
+/** @fn webViewControllerDidCancel:
+    @brief Notifies the delegate that the web view controller is being cancelled by the user.
+    @param webViewController The web view controller in question.
+ */
+- (void)webViewControllerDidCancel:(FIRAuthWebViewController *)webViewController;
+
+/** @fn webViewController:didFailWithError:
+    @brief Notifies the delegate that the web view controller failed to load a page.
+    @param webViewController The web view controller in question.
+    @param error The error that has occurred.
+ */
+- (void)webViewController:(FIRAuthWebViewController *)webViewController
+         didFailWithError:(NSError *)error;
+
+@end
+
+@interface FIRAuthWebViewController : UIViewController
+
+/** @fn initWithNibName:bundle:
+ *  @brief Please call initWithURL:delegate:
+ */
+- (instancetype)initWithNibName:(nullable NSString *)nibNameOrNil
+                         bundle:(nullable NSBundle *)nibBundleOrNil NS_UNAVAILABLE;
+
+/** @fn initWithCoder:
+ *  @brief Please call initWithURL:delegate:
+ */
+- (instancetype)initWithCoder:(NSCoder *)aDecoder NS_UNAVAILABLE;
+
+- (instancetype)initWithURL:(NSURL *)URL
+                   delegate:(__weak id<FIRAuthWebViewDelegate>)delegate
+    NS_DESIGNATED_INITIALIZER;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/FIRAuthWebViewController.m b/Firebase/Auth/Source/FIRAuthWebViewController.m
new file mode 100644
index 0000000..b9a2473
--- /dev/null
+++ b/Firebase/Auth/Source/FIRAuthWebViewController.m
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "FIRAuthWebViewController.h"
+
+#import "FIRAuthWebView.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FIRAuthWebViewController () <UIWebViewDelegate>
+@end
+
+@implementation FIRAuthWebViewController {
+  /** @var _URL
+      @brief The initial URL to display.
+   */
+  NSURL *_URL;
+
+  /** @var _delegate
+      @brief The delegate to call.
+   */
+  __weak id<FIRAuthWebViewDelegate> _delegate;
+
+  /** @var _webView;
+      @brief The web view instance for easier access.
+   */
+  __weak FIRAuthWebView *_webView;
+}
+
+- (instancetype)initWithURL:(NSURL *)URL
+                   delegate:(__weak id<FIRAuthWebViewDelegate>)delegate {
+  self = [super initWithNibName:nil bundle:nil];
+  if (self) {
+    _URL = URL;
+    _delegate = delegate;
+  }
+  return self;
+}
+
+#pragma mark - Lifecycle
+
+- (void)loadView {
+  FIRAuthWebView *webView = [[FIRAuthWebView alloc] initWithFrame:[UIScreen mainScreen].bounds];
+  webView.webView.delegate = self;
+  self.view = webView;
+  _webView = webView;
+  self.navigationItem.leftBarButtonItem =
+      [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
+                                                    target:self
+                                                    action:@selector(cancel)];
+}
+
+- (void)viewDidAppear:(BOOL)animated {
+  [super viewDidAppear:animated];
+
+  // Loads the requested URL in the web view.
+  [_webView.webView loadRequest:[NSURLRequest requestWithURL:_URL]];
+}
+
+#pragma mark - UI Targets
+
+- (void)cancel {
+  [_delegate webViewControllerDidCancel:self];
+}
+
+#pragma mark - UIWebViewDelegate
+
+- (BOOL)webView:(UIWebView *)webView
+    shouldStartLoadWithRequest:(NSURLRequest *)request
+                navigationType:(UIWebViewNavigationType)navigationType {
+  return ![_delegate webViewController:self canHandleURL:request.URL];
+}
+
+- (void)webViewDidStartLoad:(UIWebView *)webView {
+  // Show & animate the activity indicator.
+  _webView.spinner.hidden = NO;
+  [_webView.spinner startAnimating];
+}
+
+- (void)webViewDidFinishLoad:(UIWebView *)webView {
+  // Hide & stop the activity indicator.
+  _webView.spinner.hidden = YES;
+  [_webView.spinner stopAnimating];
+}
+
+- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
+  if ([error.domain isEqualToString:NSURLErrorDomain] && error.code == NSURLErrorCancelled) {
+    // It's okay for the page to be redirected before it is completely loaded.  See b/32028062 .
+    return;
+  }
+  // Forward notification to our delegate.
+  [self webViewDidFinishLoad:webView];
+  [_delegate webViewController:self didFailWithError:error];
+}
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/FirebaseCommunity.podspec b/FirebaseCommunity.podspec
index 307a93d..735dac6 100644
--- a/FirebaseCommunity.podspec
+++ b/FirebaseCommunity.podspec
@@ -45,6 +45,8 @@ Firebase Development CocoaPod including experimental and community supported fea
       'Firebase/Auth/Source/**/FIRAuthDefaultUIDelegate.[mh]',
       'Firebase/Auth/Source/**/FIRAuthUIDelegate.h',
       'Firebase/Auth/Source/**/FIRAuthURLPresenter.[mh]',
+      'Firebase/Auth/Source/**/FIRAuthWebView.[mh]',
+      'Firebase/Auth/Source/**/FIRAuthWebViewController.[mh]',
       'Firebase/Auth/Source/**/FIRPhoneAuthCredential.[mh]',
       'Firebase/Auth/Source/**/FIRPhoneAuthProvider.[mh]'
     sp.public_header_files = 'Firebase/Auth/Source/Public/*.h'