Fix failing transferToImageBitmap layout tests and commit pixel test on Mac

third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h

Index: third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h
diff --git a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h
index 8b4fc8e7439f92a8907f66b7231875cff92b76a6..f2df77d932d1d9bd19ec2dabfb47b45e49fb8436 100644
--- a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h
+++ b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferTestHelpers.h
@@ -34,7 +34,8 @@ public:
     DrawingBufferForTests(std::unique_ptr<WebGraphicsContext3DProvider> contextProvider, std::unique_ptr<Extensions3DUtil> extensionsUtil, PreserveDrawingBuffer preserve)
         : DrawingBuffer(std::move(contextProvider), std::move(extensionsUtil), false /* discardFramebufferSupported */,
             true /* wantAlphaChannel */, false /* premultipliedAlpha */, preserve, WebGL1,
-            false /* wantDepth */, false /* wantStencil */)
+            false /* wantDepth */, false /* wantStencil */,
+            DrawingBuffer::AllowChromiumImage /* ChromiumImageUsage */)
         , m_live(0)
     { }