Removing the dependency on GraphicsContext for drawing images in 2D canvas

Source/core/html/HTMLVideoElement.cpp

Index: Source/core/html/HTMLVideoElement.cpp
diff --git a/Source/core/html/HTMLVideoElement.cpp b/Source/core/html/HTMLVideoElement.cpp
index 65ec218f8e1d5b28c0de930d09954a38ff915fbe..9e3d4d1cb23a8f8c1d02698538baf5fbf709e84b 100644
--- a/Source/core/html/HTMLVideoElement.cpp
+++ b/Source/core/html/HTMLVideoElement.cpp
@@ -200,14 +200,17 @@ void HTMLVideoElement::updateDisplayState()
         setDisplayMode(Poster);
 }
 
-void HTMLVideoElement::paintCurrentFrameInContext(GraphicsContext* context, const IntRect& destRect) const
+void HTMLVideoElement::paintCurrentFrame(SkCanvas* canvas, const IntRect& destRect, const SkPaint* paint) const
 {
     if (!webMediaPlayer())
         return;
 
-    WebCanvas* canvas = context->canvas();
-    SkXfermode::Mode mode = context->compositeOperation();
-    webMediaPlayer()->paint(canvas, destRect, context->getNormalizedAlpha(), mode);
+    SkXfermode::Mode mode;
+    if (!paint || !SkXfermode::AsMode(paint->getXfermode(), &mode))
+        mode = SkXfermode::kSrcOver_Mode;
+
+    // TODO(junov, philipj): pass the whole SkPaint instead of only alpha and xfermode

[Stephen White, 2015/04/17 15:14:56]

Please add a reference in the comment to the video/shadow bug this is going to
help fix.

+    webMediaPlayer()->paint(canvas, destRect, paint ? paint->getAlpha() : 0xFF, mode);
 }
 
 bool HTMLVideoElement::copyVideoTextureToPlatformTexture(WebGraphicsContext3D* context, Platform3DObject texture, GLint level, GLenum internalFormat, GLenum type, bool premultiplyAlpha, bool flipY)
@@ -308,7 +311,7 @@ PassRefPtr<Image> HTMLVideoElement::getSourceImageForCanvas(SourceImageMode mode
         return nullptr;
     }
 
-    paintCurrentFrameInContext(imageBuffer->context(), IntRect(IntPoint(0, 0), intrinsicSize));
+    paintCurrentFrame(imageBuffer->canvas(), IntRect(IntPoint(0, 0), intrinsicSize), nullptr);
 
     *status = (mode == CopySourceImageIfVolatile) ? NormalSourceImageStatus : ExternalSourceImageStatus;
     return imageBuffer->copyImage(mode == CopySourceImageIfVolatile ? CopyBackingStore : DontCopyBackingStore, Unscaled);