Use a union typdef for the return type of canvas.getContext

third_party/WebKit/Source/modules/webgl/WebGL2RenderingContext.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebGL2RenderingContext_h
 #define WebGL2RenderingContext_h
 
 #include "core/html/canvas/CanvasRenderingContextFactory.h"
 #include "modules/webgl/WebGL2RenderingContextBase.h"
 
@@ skipping 15 matching lines @@
         CanvasRenderingContext::ContextType getContextType() const override { return CanvasRenderingContext::ContextWebgl2; }
         void onError(HTMLCanvasElement*, const String& error) override;
     };
 
     ~WebGL2RenderingContext() override;
 
     CanvasRenderingContext::ContextType getContextType() const override { return CanvasRenderingContext::ContextWebgl2; }
     unsigned version() const override { return 2; }
     String contextName() const override { return "WebGL2RenderingContext"; }
     void registerContextExtensions() override;
+    void setCanvasGetContextResult(RenderingContext&) final;
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     WebGL2RenderingContext(HTMLCanvasElement* passedCanvas, PassOwnPtr<WebGraphicsContext3D>, const WebGLContextAttributes& requestedAttributes);
 
     PersistentWillBeMember<CHROMIUMSubscribeUniform> m_chromiumSubscribeUniform;
     PersistentWillBeMember<EXTColorBufferFloat> m_extColorBufferFloat;
     PersistentWillBeMember<EXTDisjointTimerQuery> m_extDisjointTimerQuery;
     PersistentWillBeMember<EXTTextureFilterAnisotropic> m_extTextureFilterAnisotropic;
     PersistentWillBeMember<OESTextureFloatLinear> m_oesTextureFloatLinear;
     PersistentWillBeMember<WebGLCompressedTextureASTC> m_webglCompressedTextureASTC;
     PersistentWillBeMember<WebGLCompressedTextureATC> m_webglCompressedTextureATC;
     PersistentWillBeMember<WebGLCompressedTextureETC1> m_webglCompressedTextureETC1;
     PersistentWillBeMember<WebGLCompressedTexturePVRTC> m_webglCompressedTexturePVRTC;
     PersistentWillBeMember<WebGLCompressedTextureS3TC> m_webglCompressedTextureS3TC;
     PersistentWillBeMember<WebGLDebugRendererInfo> m_webglDebugRendererInfo;
     PersistentWillBeMember<WebGLDebugShaders> m_webglDebugShaders;
     PersistentWillBeMember<WebGLLoseContext> m_webglLoseContext;
 };
 
 DEFINE_TYPE_CASTS(WebGL2RenderingContext, CanvasRenderingContext, context,
     context->is3d() && WebGLRenderingContextBase::getWebGLVersion(context) == 2,
     context.is3d() && WebGLRenderingContextBase::getWebGLVersion(&context) == 2);
 
 } // namespace blink
 
 #endif