Avoid destroying surface before the parent surface stops referencing it.

ui/compositor/compositor.h

 // Copyright (c) 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 UI_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <string>
 
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
+#include "cc/surfaces/surface_sequence.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/compositor/compositor_animation_observer.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/compositor_observer.h"
 #include "ui/compositor/layer_animator_collection.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 #include "ui/gfx/vector2d.h"
 
 class SkBitmap;
 
 namespace base {
 class MessageLoopProxy;
 class RunLoop;
 }
 
 namespace cc {
 class ContextProvider;
 class Layer;
 class LayerTreeDebugState;
 class LayerTreeHost;
 class SharedBitmapManager;
+class SurfaceIdAllocator;
 }
 
 namespace gfx {
 class Rect;
 class Size;
 }
 
 namespace gpu {
 struct Mailbox;
 }
@@ skipping 38 matching lines @@
   // When true, the factory uses test contexts that do not do real GL
   // operations.
   virtual bool DoesCreateTestContexts() = 0;
 
   // Gets the shared bitmap manager for software mode.
   virtual cc::SharedBitmapManager* GetSharedBitmapManager() = 0;
 
   // Gets the compositor message loop, or NULL if not using threaded
   // compositing.
   virtual base::MessageLoopProxy* GetCompositorMessageLoop() = 0;
+  virtual scoped_ptr<cc::SurfaceIdAllocator> CreateSurfaceIdAllocator() = 0;
 };
 
 // This class represents a lock on the compositor, that can be used to prevent
 // commits to the compositor tree while we're waiting for an asynchronous
 // event. The typical use case is when waiting for a renderer to produce a frame
 // at the right size. The caller keeps a reference on this object, and drops the
 // reference once it desires to release the lock.
 // Note however that the lock is cancelled after a short timeout to ensure
 // responsiveness of the UI, so the compositor tree should be kept in a
 // "reasonable" state while the lock is held.
@@ skipping 147 matching lines @@
 
   bool IsLocked() { return compositor_lock_ != NULL; }
 
   const cc::LayerTreeDebugState& GetLayerTreeDebugState() const;
   void SetLayerTreeDebugState(const cc::LayerTreeDebugState& debug_state);
 
   LayerAnimatorCollection* layer_animator_collection() {
     return &layer_animator_collection_;
   }
 
+  cc::SurfaceSequence CreateSurfaceSequence();
+  cc::SurfaceIdAllocator* surface_id_allocator() {
+    return surface_id_allocator_.get();
+  }
+
  private:
   friend class base::RefCounted<Compositor>;
   friend class CompositorLock;
 
   // Called by CompositorLock.
   void UnlockCompositor();
 
   // Called to release any pending CompositorLock
   void CancelCompositorLock();
 
   // Notifies the compositor that compositing is complete.
   void NotifyEnd();
 
   gfx::Size size_;
 
   ui::ContextFactory* context_factory_;
 
   // The root of the Layer tree drawn by this compositor.
   Layer* root_layer_;
 
   ObserverList<CompositorObserver> observer_list_;
   ObserverList<CompositorAnimationObserver> animation_observer_list_;
 
   gfx::AcceleratedWidget widget_;
+  scoped_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
+  int surface_sequence_number_;

[jamesr, 2014/09/24 04:51:01]

uint32_t ?

   scoped_refptr<cc::Layer> root_web_layer_;
   scoped_ptr<cc::LayerTreeHost> host_;
   scoped_refptr<base::MessageLoopProxy> compositor_thread_loop_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // The manager of vsync parameters for this compositor.
   scoped_refptr<CompositorVSyncManager> vsync_manager_;
 
   // The device scale factor of the monitor that this compositor is compositing
   // layers on.
@@ skipping 18 matching lines @@
   LayerAnimatorCollection layer_animator_collection_;
 
   base::WeakPtrFactory<Compositor> schedule_draw_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_