Implement HTMLCanvasElement's transferControlToOffscreen

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/canvas2d/CanvasRenderingContext2D.h"
 
 #include "core/fetch/MemoryCache.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLDocument.h"
 #include "core/html/ImageData.h"
 #include "core/imagebitmap/ImageBitmapOptions.h"
 #include "core/loader/EmptyClients.h"
 #include "core/testing/DummyPageHolder.h"
+#include "modules/canvas/HTMLCanvasElementModule.h"
 #include "modules/canvas2d/CanvasGradient.h"
 #include "modules/canvas2d/CanvasPattern.h"
+#include "modules/offscreencanvas/OffscreenCanvas.h"
 #include "modules/webgl/WebGLRenderingContext.h"
 #include "platform/graphics/ExpensiveCanvasHeuristicParameters.h"
 #include "platform/graphics/RecordingImageBufferSurface.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkSurface.h"
 
 using ::testing::Mock;
@@ skipping 684 matching lines @@
     // Tear down the first image buffer that resides in current canvas element
     canvasElement().setSize(IntSize(20, 20));
     Mock::VerifyAndClearExpectations(fakeAccelerateSurfacePtr);
     EXPECT_EQ(400, getGlobalGPUMemoryUsage());
 
     // Tear down the second image buffer
     imageBuffer2.clear();
     EXPECT_EQ(0, getGlobalGPUMemoryUsage());
 }
 
+TEST_F(CanvasRenderingContext2DTest, TransferControlToOffscreen)

[Justin Novosad, 2016/03/30 19:51:06]

Good test, but wrong place for it. It has nothing to do with 2D contexts.  I
think a new source file is in order. Ideally it should be in the same module as
the code it tests.
third_party/WebKit/Source/modules/canvas/HTMLCanvasElementModuleTest.cpp would
make sense IMHO

+{
+    NonThrowableExceptionState exceptionState;
+    OffscreenCanvas* offscreenCanvas = HTMLCanvasElementModule::transferControlToOffscreen(canvasElement(), exceptionState);
+    HTMLCanvasElement* canvas = offscreenCanvas->getAssociatedCanvas();
+    EXPECT_EQ(canvas, canvasElement());
+}
+
 } // namespace blink