gpu: Remove WebGraphicsContext3D::makeContextCurrent() in Blink

Source/core/html/canvas/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 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 5487 matching lines @@
 #else
         m_drawingBuffer->beginDestruction();
         m_drawingBuffer.clear();
 #endif
     }
 
     blink::WebGraphicsContext3D::Attributes attributes = m_requestedAttributes->attributes(canvas()->document().topDocument().url().string(), settings, version());
     OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes, 0));
     RefPtr<DrawingBuffer> buffer;
     // Even if a non-null WebGraphicsContext3D is created, until it's made current, it isn't known whether the context is still lost.
-    if (context) {
+    if (context && context->makeContextCurrent()) {

[dshwang, 2014/08/26 18:21:47]

Currently, this code skipped the first makeContextCurrent() after
Platform::createOffscreenGraphicsContext3D(..), but other conservative
makeContextCurrent() call saves it.
Now we need makeContextCurrent() here.

         // Construct a new drawing buffer with the new WebGraphicsContext3D.
         buffer = createDrawingBuffer(context.release());
         // If DrawingBuffer::create() fails to allocate a fbo, |drawingBuffer| is set to null.
     }
     if (!buffer) {
         if (m_contextLostMode == RealLostContext) {
             m_restoreTimer.startOneShot(secondsBetweenRestoreAttempts, FROM_HERE);
         } else {
             // This likely shouldn't happen but is the best way to report it to the WebGL app.
             synthesizeGLError(GL_INVALID_OPERATION, "", "error restoring context");
@@ skipping 239 matching lines @@
     return m_sharedWebGraphicsContext3D ? m_sharedWebGraphicsContext3D->drawingBuffer() : 0;
 }
 #else
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 #endif
 
 } // namespace blink