Cleanup some dead code in blink::ImageBuffer and friends

third_party/WebKit/Source/modules/webgl/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 1310 matching lines @@
     m_markedCanvasDirty = false;
 
     if (!canvas()->buffer())
         return false;
 
     ScopedTexture2DRestorer restorer(this);
     ScopedFramebufferRestorer fboRestorer(this);
 
     drawingBuffer()->commit();
     if (!canvas()->buffer()->copyRenderingResultsFromDrawingBuffer(drawingBuffer(), sourceBuffer)) {
-        canvas()->ensureUnacceleratedImageBuffer();
-        if (canvas()->hasImageBuffer())
-            drawingBuffer()->paintRenderingResultsToCanvas(canvas()->buffer());
+        // Currently, copyRenderingResultsFromDrawingBuffer is expected to always succeed because cases
+        // where canvas()-buffer() is not accelerated are handle before reaching this point.
+        // If that assumption ever stops holding true, we may need to implement a fallback right here.
+        ASSERT_NOT_REACHED();
+        return false;
     }
 
     return true;
 }
 
 ImageData* WebGLRenderingContextBase::paintRenderingResultsToImageData(SourceDrawingBuffer sourceBuffer)
 {
     if (isContextLost())
         return nullptr;
     if (m_requestedAttributes.premultipliedAlpha())
@@ skipping 5567 matching lines @@
 
     return totalBytesPerPixel;
 }
 
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 
 } // namespace blink