cc: Fix comments in OutputSurface, it is no longer for layer compositor

cc/output/output_surface.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_OUTPUT_SURFACE_H_
 #define CC_OUTPUT_OUTPUT_SURFACE_H_
 
 #include <deque>
 #include <memory>
 
@@ skipping 19 matching lines @@
 class Size;
 class Transform;
 }
 
 namespace cc {
 
 struct ManagedMemoryPolicy;
 class OutputSurfaceClient;
 class OutputSurfaceFrame;
 
-// 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.
+// This class represents a platform-independent API for presenting
+// buffers to display via GPU or software compositing. Implementations
+// can provide platform-specific behaviour.
 class CC_EXPORT OutputSurface {
  public:
   struct Capabilities {
     Capabilities() = default;
 
     int max_frames_pending = 1;
     // Whether this output surface renders to the default OpenGL zero
     // framebuffer or to an offscreen framebuffer.
     bool uses_default_gl_framebuffer = true;
     // Whether this OutputSurface is flipped or not.
     bool flipped_output_surface = false;
   };
 
   // Constructor for GL-based compositing.
   explicit OutputSurface(scoped_refptr<ContextProvider> context_provider);
   // Constructor for software compositing.
   explicit OutputSurface(std::unique_ptr<SoftwareOutputDevice> software_device);
   // Constructor for Vulkan-based compositing.
   explicit OutputSurface(
       scoped_refptr<VulkanContextProvider> vulkan_context_provider);
 
   virtual ~OutputSurface();
 
-  // Called by the compositor on the compositor thread. This is a place where
-  // thread-specific data for the output surface can be initialized. The
-  // OutputSurface will be destroyed on the same thread that BoundToClient is
-  // called on.
+  // Called by the Display to initialize the OutputSurface. This also specifies
+  // the thread that the OutputSurface will be used on as tests create and then
+  // bind the class on different threads.
   virtual bool BindToClient(OutputSurfaceClient* 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.
   ContextProvider* context_provider() const { return context_provider_.get(); }
   VulkanContextProvider* vulkan_context_provider() const {
@@ skipping 52 matching lines @@
   std::unique_ptr<SoftwareOutputDevice> software_device_;
   base::ThreadChecker thread_checker_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_