Split WebGraphicsContext3DCommandBufferImpl::initialize() into two stages.

content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h

Index: content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
===================================================================
--- content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h	(revision 98270)
+++ content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h	(working copy)
@@ -12,6 +12,7 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "content/renderer/gpu/renderer_gl_context.h"
+#include "googleurl/src/gurl.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebGraphicsContext3D.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
@@ -57,6 +58,10 @@
                           WebKit::WebView*,
                           bool renderDirectlyToWebView);
 
+  // Must be called after initialize() and before any of the following methods.
+  // Binds this object to the current thread. We can't bind to multiple threads.
+  // TODO(husky): Document threading restrictions in WebGraphicsContext3D.h,
+  // enforce strictly in all implementations.
   virtual bool makeContextCurrent();
 
   virtual int width();
@@ -431,6 +436,12 @@
           WebGraphicsSwapBuffersCompleteCallbackCHROMIUM* callback);
 
  private:
+  // Initialize the underlying GL context. May be called multiple times; second
+  // and subsequent calls are ignored. Must be called from the thread that is
+  // going to use this object to issue GL commands (which might not be the main
+  // thread).
+  bool MaybeInitializeGL();
+
   // SwapBuffers callback.
   void OnSwapBuffersComplete();
   virtual void OnContextLost(RendererGLContext::ContextLostReason reason);
@@ -440,6 +451,11 @@
   // The GLES2Implementation we use for OpenGL rendering.
   gpu::gles2::GLES2Implementation* gl_;
 
+  // State needed by InitializeGLES2.
+  GpuChannelHost* host_;
+  GURL active_url_;
+  int32 render_view_routing_id_;
+
   bool render_directly_to_web_view_;
 #ifndef WTF_USE_THREADED_COMPOSITING
   // If rendering directly to WebView, weak pointer to it.