Revert of Add gamma/sRGB tags to SkImageInfo (patchset #1 of https://codereview.chromium.org/517123002/)

Reason for revert:
Seems to be triggering assert in blink

SSLUITest.TestRedirectHTTPToBadHTTPS (run #1):
[ RUN      ] SSLUITest.TestRedirectHTTPToBadHTTPS
HTTP server started on http://127.0.0.1:58000...
sending server_data: {"host": "127.0.0.1", "port": 58000} (36 bytes)
HTTPS server started on https://127.0.0.1:58009...
sending server_data: {"host": "127.0.0.1", "port": 58009} (36 bytes)
ASSERTION FAILED: info.fAlphaType == m_imageInfo.fAlphaType
../../third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp(78) : virtual bool blink::DecodingImageGenerator::onGetPixels(const SkImageInfo &, void *, size_t, SkPMColor *, int *)
1   0x77eb0d3 blink::DecodingImageGenerator::onGetPixels(SkImageInfo const&, void*, unsigned long, unsigned int*, int*)
2   0x92edddc SkImageGenerator::getPixels(SkImageInfo const&, void*, unsigned long, unsigned int*, int*)
3   0x92adf78 SkDiscardablePixelRef::onNewLockPixels(SkPixelRef::LockRec*)
4   0x9369283 SkPixelRef::lockPixels(SkPixelRef::LockRec*)
5   0x9369433 SkPixelRef::lockPixels()
6   0x9213344 SkBitmap::lockPixels() const
7   0x921ca57 SkAutoLockPixels::SkAutoLockPixels(SkBitmap const&, bool)
8   0x921ad80 SkAutoLockPixels::SkAutoLockPixels(SkBitmap const&, bool)
9   0x92b7125 SkDraw::drawBitmap(SkBitmap const&, SkMatrix const&, SkPaint const&) const
10  0x921f4fb SkBitmapDevice::drawBitmap(SkDraw const&, SkBitmap const&, SkMatrix const&, SkPaint const&)
11  0x921f8c7 SkBitmapDevice::drawBitmapRect(SkDraw const&, SkBitmap const&, SkRect const*, SkRect const&, SkPaint const&, SkCanvas::DrawBitmapRectFlags)
12  0x9288e12 SkCanvas::internalDrawBitmapRect(SkBitmap const&, SkRect const*, SkRect const&, SkPaint const*, SkCanvas::DrawBitmapRectFlags)
13  0x9288ee9 SkCanvas::drawBitmapRectToRect(SkBitmap const&, SkRect const*, SkRect const&, SkPaint const*, SkCanvas::DrawBitmapRectFlags)

Original issue's description:
> Add gamma/sRGB tags to SkImageInfo
>
> requires this CL to land in chrome
> https://codereview.chromium.org/517803002/
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/228b285ba14a6e9b6d1cc95ea1583caab30168a1

R=fmalita@google.com, fmalita@chromium.org, reed@chromium.org
TBR=fmalita@chromium.org, fmalita@google.com, reed@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Author: reed@google.com

Review URL: https://codereview.chromium.org/519583004

4 files changed, 46 insertions, 240 deletions

diff --git a/gyp/tests.gypi b/gyp/tests.gypi
index e4f8916637..c3b559e884 100644
--- a/gyp/tests.gypi
+++ b/gyp/tests.gypi
@@ -119,7 +119,6 @@
     '../tests/ImageDecodingTest.cpp',
     '../tests/ImageFilterTest.cpp',
     '../tests/ImageGeneratorTest.cpp',
-    '../tests/ImageInfoTest.cpp',
     '../tests/ImageIsOpaqueTest.cpp',
     '../tests/ImageNewShaderTest.cpp',
     '../tests/InfRectTest.cpp',
diff --git a/include/core/SkImageInfo.h b/include/core/SkImageInfo.h
index 7a56fb4557..3d82dc805c 100644
--- a/include/core/SkImageInfo.h
+++ b/include/core/SkImageInfo.h
@@ -135,50 +135,37 @@ bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
 /**
  *  Describe an image's dimensions and pixel type.
  */
-struct SK_API SkImageInfo {
-public:
-    SkImageInfo() {}
-
+struct SkImageInfo {
     int         fWidth;
     int         fHeight;
     SkColorType fColorType;
     SkAlphaType fAlphaType;
 
-    /*
-     *  Return an info with the specified attributes, tagged as sRGB. Note that if the requested
-     *  color type does not make sense with sRGB (e.g. kAlpha_8) then the sRGB request is ignored.
-     *
-     *  You can call isSRGB() on the returned info to determine if the request was fulfilled.
-     */
-    static SkImageInfo MakeSRGB(int width, int height, SkColorType ct, SkAlphaType at);
-    
-    /*
-     *  Return an info with the specified attributes, tagged with a specific gamma.
-     *  Note that if the requested gamma is unsupported for the requested color type, then the gamma
-     *  value will be set to 1.0 (the default).
-     *
-     *  You can call gamma() to query the resulting gamma value.
-     */
-    static SkImageInfo MakeWithGamma(int width, int height, SkColorType ct, SkAlphaType at,
-                                     float gamma);
-    
     static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at) {
-        return MakeWithGamma(width, height, ct, at, 1);
+        SkImageInfo info = {
+            width, height, ct, at
+        };
+        return info;
     }
 
     /**
      *  Sets colortype to the native ARGB32 type.
      */
     static SkImageInfo MakeN32(int width, int height, SkAlphaType at) {
-        return SkImageInfo(width, height, kN32_SkColorType, at, kExponential_Profile, 1);
+        SkImageInfo info = {
+            width, height, kN32_SkColorType, at
+        };
+        return info;
     }
 
     /**
      *  Sets colortype to the native ARGB32 type, and the alphatype to premul.
      */
     static SkImageInfo MakeN32Premul(int width, int height) {
-        return SkImageInfo(width, height, kN32_SkColorType, kPremul_SkAlphaType,
-                           kExponential_Profile, 1);
+        SkImageInfo info = {
+            width, height, kN32_SkColorType, kPremul_SkAlphaType
+        };
+        return info;
     }
 
     /**
@@ -189,17 +176,24 @@ public:
     }
 
     static SkImageInfo MakeA8(int width, int height) {
-        return SkImageInfo(width, height, kAlpha_8_SkColorType, kPremul_SkAlphaType,
-                           kUnknown_Profile, 0);
+        SkImageInfo info = {
+            width, height, kAlpha_8_SkColorType, kPremul_SkAlphaType
+        };
+        return info;
     }
 
     static SkImageInfo MakeUnknown(int width, int height) {
-        return SkImageInfo(width, height, kUnknown_SkColorType, kIgnore_SkAlphaType,
-                           kUnknown_Profile, 0);
+        SkImageInfo info = {
+            width, height, kUnknown_SkColorType, kIgnore_SkAlphaType
+        };
+        return info;
     }
 
     static SkImageInfo MakeUnknown() {
-        return SkImageInfo(0, 0, kUnknown_SkColorType, kIgnore_SkAlphaType, kUnknown_Profile, 0);
+        SkImageInfo info = {
+            0, 0, kUnknown_SkColorType, kIgnore_SkAlphaType
+        };
+        return info;
     }
 
     int width() const { return fWidth; }
@@ -242,11 +236,8 @@ public:
         return 0 != memcmp(this, &other, sizeof(other));
     }
 
-    // DEPRECATED : use the static Unflatten
     void unflatten(SkReadBuffer&);
     void flatten(SkWriteBuffer&) const;
-    
-    static SkImageInfo Unflatten(SkReadBuffer&);
 
     int64_t getSafeSize64(size_t rowBytes) const {
         if (0 == fHeight) {
@@ -265,36 +256,6 @@ public:
     }
 
     SkDEBUGCODE(void validate() const;)
-
-    /**
-     *  If the Info was tagged to be sRGB, return true, else return false.
-     */
-    bool isSRGB() const { return kSRGB_Profile == fProfile; }
-    
-    /**
-     *  If this was tagged with an explicit gamma value, return that value, else return 0.
-     *  If this was tagged as sRGB, return 0.
-     */
-    float gamma() const { return fGamma; }
-
-private:
-    enum Profile {
-        kUnknown_Profile,
-        kSRGB_Profile,
-        kExponential_Profile,
-    };
-    
-    uint32_t    fProfile;
-    float       fGamma;
-    
-    SkImageInfo(int width, int height, SkColorType ct, SkAlphaType at, Profile p, float g)
-        : fWidth(width)
-        , fHeight(height)
-        , fColorType(ct)
-        , fAlphaType(at)
-        , fProfile(p)
-        , fGamma(g)
-    {}
 };
 
 #endif
diff --git a/src/core/SkImageInfo.cpp b/src/core/SkImageInfo.cpp
index 44fd808dc8..e61cd7d45f 100644
--- a/src/core/SkImageInfo.cpp
+++ b/src/core/SkImageInfo.cpp
@@ -9,53 +9,34 @@
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 
-static bool color_type_supports_sRGB(SkColorType colorType) {
-    switch (colorType) {
-        case kRGBA_8888_SkColorType:
-        case kBGRA_8888_SkColorType:
-            return true;
-        default:
-            return false;
-    }
+static bool alpha_type_is_valid(SkAlphaType alphaType) {
+    return (alphaType >= 0) && (alphaType <= kLastEnum_SkAlphaType);
 }
 
-static bool color_type_supports_gamma(SkColorType colorType) {
-    switch (colorType) {
-        case kRGBA_8888_SkColorType:
-        case kBGRA_8888_SkColorType:
-        // case kLuminance ...
-            return true;
-        default:
-            return false;
-    }
+static bool color_type_is_valid(SkColorType colorType) {
+    return (colorType >= 0) && (colorType <= kLastEnum_SkColorType);
 }
 
-static float pin_gamma_to_legal(float gamma) {
-    if (!SkScalarIsFinite(gamma)) {
-        return 1;
-    }
-    // these limits are just made up -- feel free to change them within reason
-    const float min_gamma = 0.01f;
-    const float max_gamma = 4.0;
-    return SkScalarPin(gamma, min_gamma, max_gamma);
-}
+void SkImageInfo::unflatten(SkReadBuffer& buffer) {
+    fWidth = buffer.read32();
+    fHeight = buffer.read32();
 
-SkImageInfo SkImageInfo::MakeSRGB(int width, int height, SkColorType ct, SkAlphaType at) {
-    Profile p = color_type_supports_sRGB(ct) ? kSRGB_Profile : kUnknown_Profile;
-    return SkImageInfo(width, height, ct, at, p, 0);
+    uint32_t packed = buffer.read32();
+    SkASSERT(0 == (packed >> 16));
+    fAlphaType = (SkAlphaType)((packed >> 8) & 0xFF);
+    fColorType = (SkColorType)((packed >> 0) & 0xFF);
+    buffer.validate(alpha_type_is_valid(fAlphaType) &&
+                    color_type_is_valid(fColorType));
 }
 
-SkImageInfo SkImageInfo::MakeWithGamma(int width, int height, SkColorType ct, SkAlphaType at,
-                                       float gamma) {
-    Profile p;
-    if (color_type_supports_gamma(ct)) {
-        gamma = pin_gamma_to_legal(gamma);
-        p = kExponential_Profile;
-    } else {
-        p = kUnknown_Profile;
-        gamma = 0;
-    }
-    return SkImageInfo(width, height, ct, at, p, gamma);
+void SkImageInfo::flatten(SkWriteBuffer& buffer) const {
+    buffer.write32(fWidth);
+    buffer.write32(fHeight);
+
+    SkASSERT(0 == (fAlphaType & ~0xFF));
+    SkASSERT(0 == (fColorType & ~0xFF));
+    uint32_t packed = (fAlphaType << 8) | fColorType;
+    buffer.write32(packed);
 }
 
 bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
@@ -88,74 +69,3 @@ bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
     }
     return true;
 }
-
-void SkImageInfo::unflatten(SkReadBuffer& buffer) {
-    *this = Unflatten(buffer);
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////
-
-static bool alpha_type_is_valid(SkAlphaType alphaType) {
-    return (alphaType >= 0) && (alphaType <= kLastEnum_SkAlphaType);
-}
-
-static bool color_type_is_valid(SkColorType colorType) {
-    return (colorType >= 0) && (colorType <= kLastEnum_SkColorType);
-}
-
-static float igamma_to_gamma(int gamma3dot9) {
-    return gamma3dot9 / 512.0f;
-}
-
-static unsigned gamma_to_igamma(float gamma) {
-    SkASSERT(gamma >= 0 && gamma < 8);
-    int igamma = SkScalarRoundToInt(gamma * 512);
-    SkASSERT(igamma >= 0 && igamma <= 0xFFF);
-    return igamma;
-}
-
-SkImageInfo SkImageInfo::Unflatten(SkReadBuffer& buffer) {
-    int width = buffer.read32();
-    int height = buffer.read32();
-    uint32_t packed = buffer.read32();
-    
-    SkColorType ct = (SkColorType)((packed >> 0) & 0xFF);   // 8 bits for colortype
-    SkAlphaType at = (SkAlphaType)((packed >> 8) & 0xFF);   // 8 bits for alphatype
-    if (!alpha_type_is_valid(at) || !color_type_is_valid(ct)) {
-        return MakeUnknown();
-    }
-
-    // Earlier formats always stored 0 in the upper 16 bits. That corresponds to
-    // days before we had gamma/profile. That happens to correspond to kUnknown_Profile,
-    // which means we can just ignore the gamma value anyways.
-    //
-    int iprofile = ((packed >> 16) & 0xF);  // 4 bits for profile
-    
-    switch (iprofile) {
-        case kUnknown_Profile:
-            return Make(width, height, ct, at);
-        case kSRGB_Profile:
-            return MakeSRGB(width, height, ct, at);
-        case kExponential_Profile: {
-            int igamma = packed >> 20;      // 12 bits for gamma 3.9
-            float gamma = igamma_to_gamma(igamma);
-            return MakeWithGamma(width, height, ct, at, gamma);
-        }
-        default:
-            (void)buffer.validate(false);
-            return MakeUnknown();
-    }
-}
-
-void SkImageInfo::flatten(SkWriteBuffer& buffer) const {
-    buffer.write32(fWidth);
-    buffer.write32(fHeight);
-    
-    SkASSERT(0 == (fColorType & ~0xFF));    // 8 bits for colortype
-    SkASSERT(0 == (fAlphaType & ~0xFF));    // 8 bits for alphatype
-    SkASSERT(0 == (fProfile & ~0xF));       // 4 bits for profile
-    int igamma = gamma_to_igamma(fGamma);   // 12 bits for gamma (if needed)
- 
-    uint32_t packed = (igamma << 20) | (fProfile << 16) | (fAlphaType << 8) | fColorType;
-    buffer.write32(packed);
-}
diff --git a/tests/ImageInfoTest.cpp b/tests/ImageInfoTest.cpp
deleted file mode 100644
index 679b302ceb..0000000000
--- a/tests/ImageInfoTest.cpp
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkImageInfo.h"
-
-#include "Test.h"
-
-struct ImageInfoRec {
-    int         fWidth;
-    int         fHeight;
-    SkColorType fColorType;
-    SkAlphaType fAlphaType;
-    float       fGamma;
-    bool        fIsSRGB;
-};
-
-static void check_info(skiatest::Reporter* reporter,
-                       const ImageInfoRec& expected, const SkImageInfo& info) {
-    REPORTER_ASSERT(reporter, info.width() == expected.fWidth);
-    REPORTER_ASSERT(reporter, info.height() == expected.fHeight);
-    REPORTER_ASSERT(reporter, info.colorType() == expected.fColorType);
-    REPORTER_ASSERT(reporter, info.alphaType() == expected.fAlphaType);
-    REPORTER_ASSERT(reporter, info.gamma() == expected.fGamma);
-    REPORTER_ASSERT(reporter, info.isSRGB() == expected.fIsSRGB);
-}
-
-DEF_TEST(ImageInfo, reporter) {
-    const float nan = SK_ScalarNaN;
-    const float nice_gamma = 1.5f;
-    const int W = 100;
-    const int H = 200;
-    SkImageInfo info;
-    
-    const ImageInfoRec rec[] = {
-        { 0, 0, kUnknown_SkColorType,   kIgnore_SkAlphaType,   0, false },  // MakeUnknown()
-        { W, H, kUnknown_SkColorType,   kIgnore_SkAlphaType,   0, false },  // MakeUnknown(...)
-        { W, H, kN32_SkColorType,       kPremul_SkAlphaType,   1, false },  // MakeN32Premul(...)
-        { W, H, kN32_SkColorType,       kOpaque_SkAlphaType,   1, false },  // MakeN32(...)
-        { W, H, kAlpha_8_SkColorType,   kPremul_SkAlphaType,   0, false },  // MakeA8()
-        { W, H, kRGBA_8888_SkColorType, kUnpremul_SkAlphaType, 1, false },  // Make()
-        { W, H, kBGRA_8888_SkColorType, kPremul_SkAlphaType,   1, false },  // Make()
-        { W, H, kBGRA_8888_SkColorType, kPremul_SkAlphaType,   0, true },  // MakeSRGB()
-        { W, H, kN32_SkColorType,       kPremul_SkAlphaType,   1, false },  // MakeWithGamma() NaN
-        { W, H, kAlpha_8_SkColorType,   kPremul_SkAlphaType,   0, false },  // MakeWithGamma() bad ct for gamma
-        { W, H, kN32_SkColorType,       kPremul_SkAlphaType,   nice_gamma, false },  // MakeWithGamma() good
-    };
-
-    check_info(reporter, rec[ 0], SkImageInfo::MakeUnknown());
-    check_info(reporter, rec[ 1], SkImageInfo::MakeUnknown(W, H));
-    check_info(reporter, rec[ 2], SkImageInfo::MakeN32Premul(W, H));
-    check_info(reporter, rec[ 3], SkImageInfo::MakeN32(W, H, rec[3].fAlphaType));
-    check_info(reporter, rec[ 4], SkImageInfo::MakeA8(W, H));
-    check_info(reporter, rec[ 5], SkImageInfo::Make(W, H, rec[5].fColorType, rec[5].fAlphaType));
-    check_info(reporter, rec[ 6], SkImageInfo::Make(W, H, rec[6].fColorType, rec[6].fAlphaType));
-    check_info(reporter, rec[ 7], SkImageInfo::MakeSRGB(W, H, rec[7].fColorType, rec[7].fAlphaType));
-    check_info(reporter, rec[ 8], SkImageInfo::MakeWithGamma(W, H, rec[8].fColorType, rec[8].fAlphaType, nan));
-    check_info(reporter, rec[ 9], SkImageInfo::MakeWithGamma(W, H, rec[9].fColorType, rec[9].fAlphaType, nice_gamma));
-    check_info(reporter, rec[10], SkImageInfo::MakeWithGamma(W, H, rec[10].fColorType, rec[10].fAlphaType, rec[10].fGamma));
-}
-