Enable video painting on Canvas for Chrome on Android.

Source/WebCore/html/HTMLVideoElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 16 matching lines @@
 #if ENABLE(VIDEO)
 #include "HTMLVideoElement.h"
 
 #include "Attribute.h"
 #include "CSSPropertyNames.h"
 #include "Chrome.h"
 #include "ChromeClient.h"
 #include "Document.h"
 #include "ExceptionCode.h"
 #include "Frame.h"
+#include "GraphicsContext3D.h"
 #include "HTMLImageLoader.h"
 #include "HTMLNames.h"
 #include "HTMLParserIdioms.h"
 #include "Page.h"
 #include "RenderImage.h"
 #include "RenderVideo.h"
 #include "ScriptController.h"
 #include "Settings.h"
+#include "SharedGraphicsContext3D.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 inline HTMLVideoElement::HTMLVideoElement(const QualifiedName& tagName, Document* document, bool createdByParser)
     : HTMLMediaElement(tagName, document, createdByParser)
 {
     ASSERT(hasTagName(videoTag));
     if (document->settings())
@@ skipping 179 matching lines @@
         setDisplayMode(Poster);
 }
 
 void HTMLVideoElement::paintCurrentFrameInContext(GraphicsContext* context, const IntRect& destRect)
 {
     MediaPlayer* player = HTMLMediaElement::player();
     if (!player)
         return;
     
     player->setVisible(true); // Make player visible or it won't draw.
+
+    // Go through the fast path trying to do a GPU-GPU texture copy without a readback to system memory if possible.
+    // Otherwise, it will fallback to the normal SW path.
+    RefPtr<GraphicsContext3D> context3D = SharedGraphicsContext3D::get();
+    if (context3D && player->copyVideoTextureToCanvas(context, context3D.get()))

[scherkus (not reviewing), 2013/04/05 20:47:09]

this seems strange

there are other callers of paintCurrentFrameInContext() besides canvas

what happens in the cases where this is called but we're not painting into a
canvas?

[Ken Russell (switch to Gerrit), 2013/04/05 22:40:38]

I'll be more blunt and say that there is no way this can be doing the right
thing, because it is ignoring the destRect argument.

[hkuang, 2013/04/09 17:46:10]

Done.

[hkuang, 2013/04/09 17:46:10]

Fix the naming issue when addressing Ken's comments. Actually the backend of the
GraphicsContext is the SkCanvas.

+        return;
+
+    // Normal pure SW path
     player->paintCurrentFrameInContext(context, destRect);
 }
 
 bool HTMLVideoElement::copyVideoTextureToPlatformTexture(GraphicsContext3D* context, Platform3DObject texture, GC3Dint level, GC3Denum type, GC3Denum internalFormat, bool premultiplyAlpha, bool flipY)
 {
     if (!player())
         return false;
     return player()->copyVideoTextureToPlatformTexture(context, texture, level, type, internalFormat, premultiplyAlpha, flipY);
 }
 
@@ skipping 65 matching lines @@
 {
     String url = stripLeadingAndTrailingHTMLSpaces(imageSourceURL());
     if (url.isEmpty())
         return KURL();
     return document()->completeURL(url);
 }
 
 }
 
 #endif