cc: Route offscreen context creation for compositor to the browser.

cc/resource_provider.h

Index: cc/resource_provider.h
diff --git a/cc/resource_provider.h b/cc/resource_provider.h
index 5b31139bdee2748d7afe8febd68db9ac9b609831..5b62c9ceb08a8ec1cf01804cb9d4405e949c6a2d 100644
--- a/cc/resource_provider.h
+++ b/cc/resource_provider.h
@@ -28,6 +28,10 @@ namespace WebKit {
 class WebGraphicsContext3D;
 }
 
+namespace ui {
+class ContextProvider;
+}
+
 namespace gfx {
 class Rect;
 class Vector2d;
@@ -263,6 +267,9 @@ public:
     // Indicates if we can currently lock this resource for write.
     bool canLockForWrite(ResourceId);
 
+    ui::ContextProvider* offscreenContextProvider() { return m_offscreenContextProvider.get(); }
+    void setOffscreenContextProvider(scoped_refptr<ui::ContextProvider> offscreenContextProvider);
+
 private:
     struct Resource {
         Resource();
@@ -334,6 +341,8 @@ private:
     int m_maxTextureSize;
     GLenum m_bestTextureFormat;
 
+    scoped_refptr<ui::ContextProvider> m_offscreenContextProvider;
+
     base::ThreadChecker m_threadChecker;
 
     scoped_refptr<Fence> m_currentReadLockFence;