Remove existingDrawingContext from HTMLCanvasElement

Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 723 matching lines @@
     // Subtracting two intptr_t that are known to be positive will never underflow.
     v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(externallyAllocatedMemory - m_externallyAllocatedMemory);
     m_externallyAllocatedMemory = externallyAllocatedMemory;
 }
 
 GraphicsContext* HTMLCanvasElement::drawingContext() const
 {
     return buffer() ? m_imageBuffer->context() : nullptr;
 }
 
-GraphicsContext* HTMLCanvasElement::existingDrawingContext() const
-{
-    if (!hasImageBuffer())
-        return nullptr;
-
-    return drawingContext();
-}
-
 SkCanvas* HTMLCanvasElement::drawingCanvas() const
 {
     return buffer() ? m_imageBuffer->canvas() : nullptr;
 }
 
 SkCanvas* HTMLCanvasElement::existingDrawingCanvas() const
 {
     if (!hasImageBuffer())
         return nullptr;
 
@@ skipping 131 matching lines @@
 {
     return FloatSize(width(), height());
 }
 
 bool HTMLCanvasElement::isOpaque() const
 {
     return m_context && !m_context->hasAlpha();
 }
 
 } // blink