aura: Remove CreateOffscreenContext from ui::ContextFactory.

cc/test/fake_layer_tree_host_client.h

Index: cc/test/fake_layer_tree_host_client.h
diff --git a/cc/test/fake_layer_tree_host_client.h b/cc/test/fake_layer_tree_host_client.h
index 47c4e27fb9267ef95645759259be023216b1d339..c5674d4aa0db661f566692070d196efd37df5917 100644
--- a/cc/test/fake_layer_tree_host_client.h
+++ b/cc/test/fake_layer_tree_host_client.h
@@ -6,12 +6,12 @@
 #define CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 
 #include "base/memory/scoped_ptr.h"
+#include "cc/debug/fake_context_provider.h"
 #include "cc/input/input_handler.h"
-#include "cc/test/fake_context_provider.h"
-#include "cc/test/fake_output_surface.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
+class OutputSurface;
 
 class FakeLayerTreeHostClient : public LayerTreeHostClient {
  public: