Implement offscreenCanvas.getContext('webgl') on a worker thread

content/renderer/renderer_blink_platform_impl.h

Index: content/renderer/renderer_blink_platform_impl.h
diff --git a/content/renderer/renderer_blink_platform_impl.h b/content/renderer/renderer_blink_platform_impl.h
index b758d2879075e1d5d57e327a375f9bc54d216bd9..3374e0fc13240c886d68c262d5d94ea0b3d30c17 100644
--- a/content/renderer/renderer_blink_platform_impl.h
+++ b/content/renderer/renderer_blink_platform_impl.h
@@ -176,7 +176,8 @@ class CONTENT_EXPORT RendererBlinkPlatformImpl : public BlinkPlatformImpl {
       const blink::Platform::ContextAttributes& attributes,
       const blink::WebURL& top_document_web_url,
       blink::WebGraphicsContext3DProvider* share_provider,
-      blink::Platform::GraphicsInfo* gl_info) override;
+      blink::Platform::GraphicsInfo* gl_info,
+      blink::Platform::WillBindToCurrentThread) override;
   blink::WebGraphicsContext3DProvider*
   createSharedOffscreenGraphicsContext3DProvider() override;
   blink::WebCompositorSupport* compositorSupport() override;