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

third_party/WebKit/public/platform/Platform.h

Index: third_party/WebKit/public/platform/Platform.h
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index c7a244b6d8c49c5092b4e12956fe58912cc74be4..050f06ceb5ff8316c9ce46ec7d2059356cd69d4b 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -463,6 +463,10 @@ public:
         WebString driverVersion;
         WebString errorMessage;
     };
+    enum WillBindToCurrentThread {
+        BindToCurrentThread,
+        DoNotBindToCurrentThread
+    };
     // Returns a newly allocated and initialized offscreen context provider,
     // backed by an independent context. Returns null if the context cannot be
     // created or initialized.
@@ -472,7 +476,8 @@ public:
         const ContextAttributes&,
         const WebURL& topDocumentURL,
         WebGraphicsContext3DProvider* shareContext,
-        GraphicsInfo*) { return nullptr; }
+        GraphicsInfo*,
+        WillBindToCurrentThread) { return nullptr; }
 
     // Returns a newly allocated and initialized offscreen context provider,
     // backed by the process-wide shared main thread context. Returns null if