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 6657f59a8f268e8e7e4004810d31d3a327f28e41..955e66a7609402872a95590ecef419b020c6079b 100644
--- a/cc/layer_tree_host_client.h
+++ b/cc/layer_tree_host_client.h
@@ -11,6 +11,9 @@ namespace gfx {
 class Vector2d;
 }
 
+class GrContext;
+namespace WebKit { class WebGraphicsContext3D; }
+
 namespace cc {
 class FontAtlas;
 class InputHandler;
@@ -26,6 +29,15 @@ public:
     virtual void applyScrollAndScale(gfx::Vector2d scrollDelta, float pageScale) = 0;
     virtual scoped_ptr<OutputSurface> createOutputSurface() = 0;
     virtual void didRecreateOutputSurface(bool success) = 0;
+    // This method should create a context if needed, but only one valid context
+    // should ever be created by the client to return from this method.
+    virtual WebKit::WebGraphicsContext3D* OffscreenContext3dForMainThread() = 0;
+    // This method should create a context if needed, but only one valid context
+    // should ever be created by the client to return from this method.
+    virtual WebKit::WebGraphicsContext3D* OffscreenContext3dForCompositorThread() = 0;
+    virtual GrContext* OffscreenGrContextForMainThread() = 0;
+    virtual GrContext* OffscreenGrContextForCompositorThread() = 0;
+    virtual void DestroyOffscreenContext3dForCompositorThread() = 0;
     virtual scoped_ptr<InputHandler> createInputHandler() = 0;
     virtual void willCommit() = 0;
     virtual void didCommit() = 0;
@@ -38,6 +50,9 @@ public:
     // Creates a font atlas to use for debug visualizations.
     virtual scoped_ptr<FontAtlas> createFontAtlas() = 0;
 
+    // This hook is for testing.
+    virtual void willRetryRecreateOutputSurface() {}
+
 protected:
     virtual ~LayerTreeHostClient() { }
 };