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

cc/layer_tree_host_client.h

Index: cc/layer_tree_host_client.h
diff --git a/cc/layer_tree_host_client.h b/cc/layer_tree_host_client.h
index 25d93aef468f9166277809bcead82eaa383b4daa..d3e61ce2ee5eb289b45646c50cccb94ba77b5c12 100644
--- a/cc/layer_tree_host_client.h
+++ b/cc/layer_tree_host_client.h
@@ -5,12 +5,15 @@
 #ifndef CC_LAYER_TREE_HOST_CLIENT_H_
 #define CC_LAYER_TREE_HOST_CLIENT_H_
 
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace gfx {
 class Vector2d;
 }
 
+namespace ui { class ContextProvider; }
+
 namespace cc {
 class InputHandler;
 class OutputSurface;
@@ -34,6 +37,13 @@ public:
     // Used only in the single-threaded path.
     virtual void scheduleComposite() = 0;
 
+    // These must always return a valid ContextProvider. But the provider does not need to be capable of creating contexts.
+    virtual scoped_refptr<ui::ContextProvider> OffscreenContextProviderForMainThread() = 0;
+    virtual scoped_refptr<ui::ContextProvider> OffscreenContextProviderForCompositorThread() = 0;
+
+    // This hook is for testing.
+    virtual void willRetryRecreateOutputSurface() {}
+
 protected:
     virtual ~LayerTreeHostClient() { }
 };