cc: Stop calling DetachFromClient if bind failed.

cc/output/compositor_frame_sink.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_OUTPUT_COMPOSITOR_FRAME_SINK_H_
 #define CC_OUTPUT_COMPOSITOR_FRAME_SINK_H_
 
 #include <deque>
 #include <memory>
 
@@ skipping 18 matching lines @@
 class Size;
 class Transform;
 }
 
 namespace cc {
 
 class CompositorFrame;
 struct ManagedMemoryPolicy;
 class CompositorFrameSinkClient;
 
-// Represents the output surface for a compositor. The compositor owns
-// and manages its destruction. Its lifetime is:
-//   1. Created on the main thread by the LayerTreeHost through its client.
-//   2. Passed to the compositor thread and bound to a client via BindToClient.
-//      From here on, it will only be used on the compositor thread.
-//   3. If the 3D context is lost, then the compositor will delete the output
-//      surface (on the compositor thread) and go back to step 1.
+// An interface for submitting CompositorFrames to a display compositor
+// which will compose frames from multiple CompositorFrameSinks to show
+// on screen to the user.
+// If a context_provider() is present, frames should be submitted with
+// OpenGL resources (created with the context_provider()). If not, then
+// SharedBitmap resources should be used.
 class CC_EXPORT CompositorFrameSink {
  public:
   struct Capabilities {
     Capabilities() = default;
 
     // Whether ForceReclaimResources can be called to reclaim all resources
     // from the CompositorFrameSink.
     bool can_force_reclaim_resources = false;
     // True if sync points for resources are needed when swapping delegated
     // frames.
     bool delegated_sync_points_required = true;
   };
 
-  // Constructor for GL-based and/or software compositing.
+  // Constructor for GL-based and/or software resources.
   CompositorFrameSink(scoped_refptr<ContextProvider> context_provider,
                       scoped_refptr<ContextProvider> worker_context_provider);
 
-  // Constructor for Vulkan-based compositing.
+  // Constructor for Vulkan-based resources.
   explicit CompositorFrameSink(
       scoped_refptr<VulkanContextProvider> vulkan_context_provider);
 
   virtual ~CompositorFrameSink();
 
   // Called by the compositor on the compositor thread. This is a place where
   // thread-specific data for the output surface can be initialized, since from
   // this point to when DetachFromClient() is called the output surface will
   // only be used on the compositor thread.
   // The caller should call DetachFromClient() on the same thread before
   // destroying the CompositorFrameSink, even if this fails. And BindToClient
   // should not be called twice for a given CompositorFrameSink.
   virtual bool BindToClient(CompositorFrameSinkClient* client);
 
-  // Called by the compositor on the compositor thread. This is a place where
-  // thread-specific data for the output surface can be uninitialized.
+  // Must be called from the thread where BindToClient was called if
+  // BindToClient succeeded, after which the CompositorFrameSink may be
+  // destroyed from any thread. This is a place where thread-specific data for
+  // the object can be uninitialized.
   virtual void DetachFromClient();
 
   bool HasClient() { return !!client_; }
 
   const Capabilities& capabilities() const { return capabilities_; }
 
-  // Obtain the 3d context or the software device associated with this output
-  // surface. Either of these may return a null pointer, but not both.
-  // In the event of a lost context, the entire output surface should be
-  // recreated.
+  // The ContextProviders may be null if frames should be submitted with
+  // software SharedBitmap resources.
   ContextProvider* context_provider() const { return context_provider_.get(); }
   ContextProvider* worker_context_provider() const {
     return worker_context_provider_.get();
   }
   VulkanContextProvider* vulkan_context_provider() const {
     return vulkan_context_provider_.get();
   }
 
   // If supported, this causes a ReclaimResources for all resources that are
   // currently in use.
@@ skipping 17 matching lines @@
 
   CompositorFrameSinkClient* client_ = nullptr;
 
   struct CompositorFrameSink::Capabilities capabilities_;
   scoped_refptr<ContextProvider> context_provider_;
   scoped_refptr<ContextProvider> worker_context_provider_;
   scoped_refptr<VulkanContextProvider> vulkan_context_provider_;
   base::ThreadChecker client_thread_checker_;
 
  private:
-  void DetachFromClientInternal();
-
   DISALLOW_COPY_AND_ASSIGN(CompositorFrameSink);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COMPOSITOR_FRAME_SINK_H_