ozone: Clarify All SurfaceFactoryOzone APIs except for CreateNativePixmap() must be used on the mai…

ui/ozone/public/surface_factory_ozone.h

 // Copyright (c) 2013 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 UI_OZONE_PUBLIC_SURFACE_FACTORY_OZONE_H_
 #define UI_OZONE_PUBLIC_SURFACE_FACTORY_OZONE_H_
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/native_library.h"
@@ skipping 111 matching lines @@
   // caller. desired_list contains list of desired EGL properties and values.
   virtual const int32* GetEGLSurfaceProperties(const int32* desired_list);
 
   // Get the hal struct to check for overlay support.
   virtual OverlayCandidatesOzone* GetOverlayCandidates(
       gfx::AcceleratedWidget w);
 
   // Create a single native buffer to be used for overlay planes or zero copy
   // for |widget| representing a particular display controller or default
   // display controller for kNullAcceleratedWidget.
+  // It can be called on any thread.
   virtual scoped_refptr<NativePixmap> CreateNativePixmap(
       gfx::AcceleratedWidget widget,
       gfx::Size size,
       BufferFormat format,
       BufferUsage usage);
 
   // Sets the overlay plane to switch to at the next page flip.
   // |w| specifies the screen to display this overlay plane on.
   // |plane_z_order| specifies the stacking order of the plane relative to the
   // main framebuffer located at index 0.
@@ skipping 20 matching lines @@
   // such as MAP for zero copy or SCANOUT for display controller.
   virtual bool CanCreateNativePixmap(BufferUsage usage);
 
  private:
   static SurfaceFactoryOzone* impl_;  // not owned
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PUBLIC_SURFACE_FACTORY_OZONE_H_