80% of calls to skia::GetTopDevice() were retrieving a read-only refe…

…rence to the raw pixel data; this CL simplifies those call sites and migrates to a more GPU-friendly and less internals-exposing implementation.

BUG=543755

Review URL: https://codereview.chromium.org/1399223004

Cr-Commit-Position: refs/heads/master@{#355104}

chrome/browser/thumbnails/content_analysis_unittest.cc

@@ -84,8 +84,7 @@ TEST_F(ThumbnailContentAnalysisTest, ApplyGradientMagnitudeOnImpulse) {
   canvas.FillRect(gfx::Rect(0, 0, 800, 600), SkColorSetRGB(10, 10, 10));
   canvas.FillRect(gfx::Rect(400, 300, 1, 1), SkColorSetRGB(255, 255, 255));
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
 
   SkBitmap reduced_color;
   reduced_color.allocPixels(SkImageInfo::MakeA8(source.width(),
@@ -128,8 +127,7 @@ TEST_F(ThumbnailContentAnalysisTest, ApplyGradientMagnitudeOnFrame) {
   canvas.FillRect(gfx::Rect(0, 0, 800, 600), SkColorSetRGB(0, 0, 0));
   canvas.DrawRect(draw_rect, SkColorSetRGB(255, 255, 255));
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
 
   SkBitmap reduced_color;
   reduced_color.allocPixels(SkImageInfo::MakeA8(source.width(),
@@ -167,8 +165,7 @@ TEST_F(ThumbnailContentAnalysisTest, ExtractImageProfileInformation) {
   canvas.FillRect(image_rect, SkColorSetRGB(0, 0, 0));
   canvas.DrawRect(draw_rect, SkColorSetRGB(255, 255, 255));
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap reduced_color;
   reduced_color.allocPixels(SkImageInfo::MakeA8(source.width(),
                                                 source.height()));
@@ -231,8 +228,7 @@ TEST_F(ThumbnailContentAnalysisTest,
   canvas.DrawRect(gfx::Rect(300, 250, 99, 100), SkColorSetRGB(255, 255, 255));
   canvas.DrawRect(gfx::Rect(401, 250, 99, 100), SkColorSetRGB(255, 255, 255));
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap reduced_color;
   reduced_color.allocPixels(SkImageInfo::MakeA8(source.width(),
                                                 source.height()));
@@ -573,8 +569,7 @@ TEST_F(ThumbnailContentAnalysisTest, ComputeDecimatedImage) {
   std::fill_n(columns.begin() + 300, 100, true);
   std::fill_n(columns.begin() + 500, 100, true);
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap result = ComputeDecimatedImage(source, rows, columns);
   EXPECT_FALSE(result.empty());
   EXPECT_EQ(300, result.width());
@@ -686,8 +681,7 @@ TEST_F(ThumbnailContentAnalysisTest, CreateRetargetedThumbnailImage) {
     canvas.DrawRect(pict_rect, SkColorSetRGB(0, 0, 0));
   }
 
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
 
   SkBitmap result = CreateRetargetedThumbnailImage(
       source, gfx::Size(424, 264), 2.5);

chrome/browser/thumbnails/content_based_thumbnailing_algorithm_unittest.cc

@@ -137,8 +137,7 @@ TEST_F(ContentBasedThumbnailingAlgorithmTest, CreateRetargetedThumbnail) {
 
   // The image consists of vertical non-overlapping stripes 150 pixels wide.
   canvas.FillRect(gfx::Rect(200, 200, 800, 400), SkColorSetRGB(255, 255, 255));
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
 
   ConsumerCallbackCatcher catcher;
   const gfx::Size thumbnail_size(432, 284);

chrome/browser/thumbnails/simple_thumbnail_crop_unittest.cc

@@ -26,8 +26,7 @@ typedef testing::Test SimpleThumbnailCropTest;
 TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_TallerThanWide) {
   // The input bitmap is vertically long.
   gfx::Canvas canvas(gfx::Size(40, 90), 1.0f, true);
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // The desired size is square.
   thumbnails::ClipResult clip_result = thumbnails::CLIP_RESULT_NOT_CLIPPED;
@@ -43,8 +42,7 @@ TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_TallerThanWide) {
 TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_WiderThanTall) {
   // The input bitmap is horizontally long.
   gfx::Canvas canvas(gfx::Size(70, 40), 1.0f, true);
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // The desired size is square.
   thumbnails::ClipResult clip_result = thumbnails::CLIP_RESULT_NOT_CLIPPED;
@@ -60,8 +58,7 @@ TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_WiderThanTall) {
 TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_TooWiderThanTall) {
   // The input bitmap is horizontally very long.
   gfx::Canvas canvas(gfx::Size(90, 40), 1.0f, true);
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // The desired size is square.
   thumbnails::ClipResult clip_result = thumbnails::CLIP_RESULT_NOT_CLIPPED;
@@ -77,8 +74,7 @@ TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_TooWiderThanTall) {
 TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_NotClipped) {
   // The input bitmap is square.
   gfx::Canvas canvas(gfx::Size(40, 40), 1.0f, true);
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // The desired size is square.
   thumbnails::ClipResult clip_result = thumbnails::CLIP_RESULT_NOT_CLIPPED;
@@ -94,8 +90,7 @@ TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_NotClipped) {
 TEST_F(SimpleThumbnailCropTest, GetClippedBitmap_NonSquareOutput) {
   // The input bitmap is square.
   gfx::Canvas canvas(gfx::Size(40, 40), 1.0f, true);
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // The desired size is horizontally long.
   thumbnails::ClipResult clip_result = thumbnails::CLIP_RESULT_NOT_CLIPPED;

components/test_runner/web_test_proxy.cc

@@ -600,8 +600,7 @@ void WebTestProxyBase::CapturePixelsForPrinting(
   web_frame->printEnd();
 
   DrawSelectionRect(canvas.get());
-  SkBaseDevice* device = skia::GetTopDevice(*canvas);
-  const SkBitmap& bitmap = device->accessBitmap(false);
+  const SkBitmap bitmap = skia::ReadPixels(canvas.get());
   callback.Run(bitmap);
 }
 

content/renderer/pepper/plugin_instance_throttler_impl_unittest.cc

@@ -99,8 +99,7 @@ TEST_F(PluginInstanceThrottlerImplTest, ThrottleByKeyframe) {
   gfx::Canvas canvas(gfx::Size(20, 10), 1.0f, true);
   canvas.FillRect(gfx::Rect(20, 10), SK_ColorBLACK);
   canvas.FillRect(gfx::Rect(10, 10), SK_ColorWHITE);
-  SkBitmap interesting_bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap interesting_bitmap = skia::ReadPixels(canvas.sk_canvas());
 
   // Don't throttle for a boring frame.
   throttler()->OnImageFlush(&boring_bitmap);

skia/ext/platform_canvas.cc

@@ -13,6 +13,13 @@ SkBaseDevice* GetTopDevice(const SkCanvas& canvas) {
   return canvas.getTopDevice(true);
 }
 
+SkBitmap ReadPixels(SkCanvas* canvas) {
+  SkBitmap bitmap;
+  bitmap.setInfo(canvas->imageInfo());
+  canvas->readPixels(&bitmap, 0, 0);
+  return bitmap;
+}
+
 bool SupportsPlatformPaint(const SkCanvas* canvas) {
   PlatformDevice* platform_device = GetPlatformDevice(GetTopDevice(*canvas));
   return platform_device && platform_device->SupportsPlatformPaint();

skia/ext/platform_canvas.h

@@ -116,6 +116,13 @@ SK_API size_t PlatformCanvasStrideForWidth(unsigned width);
 // by the next call to save() or restore().
 SK_API SkBaseDevice* GetTopDevice(const SkCanvas& canvas);
 
+// Copies pixels from the SkCanvas into an SkBitmap, fetching pixels from
+// GPU memory if necessary.
+//
+// The bitmap will remain empty if we can't allocate enough memory for a copy
+// of the pixels.
+SK_API SkBitmap ReadPixels(SkCanvas* canvas);
+
 // Returns true if native platform routines can be used to draw on the
 // given canvas. If this function returns false, BeginPlatformPaint will
 // return NULL PlatformSurface.

skia/ext/platform_canvas_unittest.cc

@@ -42,8 +42,7 @@ bool IsOfColor(const SkBitmap& bitmap, int x, int y, uint32_t color) {
 bool VerifyRect(const PlatformCanvas& canvas,
                 uint32_t canvas_color, uint32_t rect_color,
                 int x, int y, int w, int h) {
-  SkBaseDevice* device = skia::GetTopDevice(canvas);
-  const SkBitmap& bitmap = device->accessBitmap(false);
+  const SkBitmap bitmap = skia::ReadPixels(const_cast<PlatformCanvas*>(&canvas));
   SkAutoLockPixels lock(bitmap);
 
   for (int cur_y = 0; cur_y < bitmap.height(); cur_y++) {

ui/gfx/blit_unittest.cc

@@ -40,8 +40,7 @@ void SetToCanvas(skia::PlatformCanvas* canvas, uint8 values[h][w]) {
 // bitmap (see SetToCanvas above).
 template<int w, int h>
 void VerifyCanvasValues(skia::PlatformCanvas* canvas, uint8 values[h][w]) {
-  SkBitmap& bitmap = const_cast<SkBitmap&>(
-      skia::GetTopDevice(*canvas)->accessBitmap(true));
+  SkBitmap bitmap = skia::ReadPixels(canvas);
   SkAutoLockPixels lock(bitmap);
   ASSERT_EQ(w, bitmap.width());
   ASSERT_EQ(h, bitmap.height());

ui/gfx/color_analysis_unittest.cc

@@ -342,8 +342,7 @@ TEST_F(ColorAnalysisTest, ComputeColorCovarianceWithCanvas) {
   canvas.FillRect(gfx::Rect(150, 0, 50, 200), SkColorSetRGB(0, 100, 100));
   canvas.FillRect(gfx::Rect(200, 0, 50, 200), SkColorSetRGB(0, 0, 100));
 
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
   gfx::Matrix3F covariance = ComputeColorCovariance(bitmap);
 
   gfx::Matrix3F expected_covariance = gfx::Matrix3F::Zeros();
@@ -401,8 +400,7 @@ TEST_F(ColorAnalysisTest, ApplyColorReductionBlackAndWhite) {
   // The image consists of vertical non-overlapping stripes 150 pixels wide.
   canvas.FillRect(gfx::Rect(0, 0, 150, 200), SkColorSetRGB(0, 0, 0));
   canvas.FillRect(gfx::Rect(150, 0, 150, 200), SkColorSetRGB(255, 255, 255));
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap result;
   result.allocPixels(SkImageInfo::MakeA8(300, 200));
 
@@ -439,8 +437,7 @@ TEST_F(ColorAnalysisTest, ApplyColorReductionMultiColor) {
   canvas.FillRect(gfx::Rect(0, 0, 100, 200), SkColorSetRGB(100, 0, 0));
   canvas.FillRect(gfx::Rect(100, 0, 100, 200), SkColorSetRGB(0, 255, 0));
   canvas.FillRect(gfx::Rect(200, 0, 100, 200), SkColorSetRGB(0, 0, 128));
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap result;
   result.allocPixels(SkImageInfo::MakeA8(300, 200));
 
@@ -482,8 +479,7 @@ TEST_F(ColorAnalysisTest, ComputePrincipalComponentImage) {
   canvas.FillRect(gfx::Rect(0, 0, 100, 200), SkColorSetRGB(10, 10, 10));
   canvas.FillRect(gfx::Rect(100, 0, 100, 200), SkColorSetRGB(100, 100, 100));
   canvas.FillRect(gfx::Rect(200, 0, 100, 200), SkColorSetRGB(255, 255, 255));
-  SkBitmap source =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap source = skia::ReadPixels(canvas.sk_canvas());
   SkBitmap result;
   result.allocPixels(SkImageInfo::MakeA8(300, 200));
 

ui/gfx/color_utils_unittest.cc

@@ -127,8 +127,7 @@ TEST(ColorUtils, CalculateBoringScore_SingleColor) {
   // Fill all pixels in black.
   canvas.FillRect(gfx::Rect(kSize), SK_ColorBLACK);
 
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
   // The thumbnail should deserve the highest boring score.
   EXPECT_DOUBLE_EQ(1.0, CalculateBoringScore(bitmap));
 }
@@ -143,8 +142,7 @@ TEST(ColorUtils, CalculateBoringScore_TwoColors) {
   canvas.FillRect(gfx::Rect(0, 0, kSize.width() / 2, kSize.height()),
                   SK_ColorWHITE);
 
-  SkBitmap bitmap =
-      skia::GetTopDevice(*canvas.sk_canvas())->accessBitmap(false);
+  SkBitmap bitmap = skia::ReadPixels(canvas.sk_canvas());
   ASSERT_EQ(kSize.width(), bitmap.width());
   ASSERT_EQ(kSize.height(), bitmap.height());
   // The thumbnail should be less boring because two colors are used.