Revert of remove unused (by clients) SkPathUtils (patchset #1 id:1 of https://codereview.chromium.org/1088383003/)

Reason for revert:
This change is causing the DEPS roll to fail:

http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromium_gn_compile_rel/builds/78771/steps/gn/logs/stdio

Original issue's description:
> remove unused (by clients) SkPathUtils
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/aab35d91b8b80acd1902594bbf542083fdfa4bb7

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

Review URL: https://codereview.chromium.org/1060703003

1 files changed, 152 insertions, 0 deletions

diff --git a/tests/PathUtilsTest.cpp b/tests/PathUtilsTest.cpp
new file mode 100644
index 0000000000..4dfeda467c
--- /dev/null
+++ b/tests/PathUtilsTest.cpp
@@ -0,0 +1,152 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkPathUtils.h"
+#include "SkRandom.h"
+#include "SkTime.h"
+#include "Test.h"
+
+const int kNumIt = 100;
+
+static void fill_random_bits(int chars, char* bits){
+    SkRandom rand(SkTime::GetMSecs());
+
+    for (int i = 0; i < chars; ++i){
+        bits[i] = rand.nextU();
+    }
+}
+
+static int get_bit(const char* buffer, int x) {
+    int byte = x >> 3;
+    int bit = x & 7;
+
+    return buffer[byte] & (128 >> bit);
+}
+
+/* // useful for debugging errors
+   #include <iostream>
+static void print_bits( const char* bits, int w, int h) {
+
+    for (int y = 0; y < h; ++y) {
+        for (int x = 0; x < w; ++x){
+            bool bit = get_bit(&bits[y], x)!=0;
+            std::cout << bit;
+            }
+        std::cout << std::endl;
+    }
+}
+
+static void print_bmp( SkBitmap* bmp, int w, int h){
+
+    for (int y = 0; y < h; ++y) {
+        for (int x = 0; x < w; ++x) {
+            int d = *bmp->getAddr32(x,y);
+            if (d == -1)
+                std::cout << 0;
+            else
+                std::cout << 1;
+        }
+        std::cout << std::endl;
+    }
+}
+*/
+
+static void binary_to_skbitmap(const char* bin_bmp, SkBitmap* sk_bmp,
+                         int w, int h, int rowBytes){
+    //init the SkBitmap
+    sk_bmp->allocN32Pixels(w, h);
+
+    for (int y = 0; y < h; ++y) { // for every row
+
+        const char* curLine = &bin_bmp[y * rowBytes];
+        for (int x = 0; x < w; ++x) {// for every pixel
+            if (get_bit(curLine, x)) {
+                *sk_bmp->getAddr32(x,y) = SK_ColorBLACK;
+            }
+            else {
+                *sk_bmp->getAddr32(x,y) = SK_ColorWHITE;
+            }
+        }
+    }
+}
+
+static bool test_bmp(skiatest::Reporter* reporter,
+                      const SkBitmap* bmp1, const SkBitmap* bmp2,
+                      int w, int h) {
+    for (int y = 0; y < h; ++y) { // loop through all pixels
+        for (int x = 0; x < w; ++x) {
+            REPORTER_ASSERT( reporter, *bmp1->getAddr32(x,y) == *bmp2->getAddr32(x,y) );
+        }
+    }
+    return true;
+}
+
+static void test_path_eq(skiatest::Reporter* reporter, const SkPath* path,
+                      const SkBitmap* truth, int w, int h){
+    // make paint
+    SkPaint bmpPaint;
+    bmpPaint.setAntiAlias(true);  // Black paint for bitmap
+    bmpPaint.setStyle(SkPaint::kFill_Style);
+    bmpPaint.setColor(SK_ColorBLACK);
+
+    // make bmp
+    SkBitmap bmp;
+    bmp.allocN32Pixels(w, h);
+    SkCanvas canvas(bmp);
+    canvas.clear(SK_ColorWHITE);
+    canvas.drawPath(*path, bmpPaint);
+
+    // test bmp
+    test_bmp(reporter, truth, &bmp, w, h);
+}
+
+static void test_path(skiatest::Reporter* reporter, const SkBitmap* truth,
+                            const char* bin_bmp, int w, int h, int rowBytes){
+    // make path
+    SkPath path;
+    SkPathUtils::BitsToPath_Path(&path, bin_bmp, w, h, rowBytes);
+
+    //test for correctness
+    test_path_eq(reporter, &path, truth, w, h);
+}
+
+static void test_region(skiatest::Reporter* reporter, const SkBitmap* truth,
+                            const char* bin_bmp, int w, int h, int rowBytes){
+    //generate bitmap
+    SkPath path;
+    SkPathUtils::BitsToPath_Region(&path, bin_bmp, w, h, rowBytes);
+
+    //test for correctness
+    test_path_eq(reporter, &path, truth, w, h);
+}
+
+DEF_TEST(PathUtils, reporter) {
+    const int w[] = {4, 8, 12, 16};
+    const int h = 8, rowBytes = 4;
+
+    char bits[ h * rowBytes ];
+    static char* binBmp = &bits[0];
+
+    //loop to run randomized test lots of times
+    for (int it = 0; it < kNumIt; ++it)
+    {
+        // generate a random binary bitmap
+        fill_random_bits( h * rowBytes, binBmp); // generate random bitmap
+
+        // for each bitmap width, use subset of binary bitmap
+        for (unsigned int i = 0; i < SK_ARRAY_COUNT(w); ++i) {
+            // generate truth bitmap
+            SkBitmap bmpTruth;
+            binary_to_skbitmap(binBmp, &bmpTruth, w[i], h, rowBytes);
+
+            test_path(reporter, &bmpTruth, binBmp, w[i], h, rowBytes);
+            test_region(reporter, &bmpTruth, binBmp, w[i], h, rowBytes);
+        }
+    }
+}