Allow ui::Compositor to disable commits during tab-switch

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"
@@ skipping 93 matching lines @@
   // Resize the display corresponding to this compositor to a particular size.
   virtual void ResizeDisplay(ui::Compositor* compositor,
                              const gfx::Size& size) = 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
+// By default, the lock will be 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.
+// "reasonable" state while the lock is held. If the compositor sets
+// locks to not time out, then the lock will remain in effect until destroyed.
 // Don't instantiate this class directly, use Compositor::GetCompositorLock.
 class COMPOSITOR_EXPORT CompositorLock
     : public base::RefCounted<CompositorLock>,
       public base::SupportsWeakPtr<CompositorLock> {
  private:
   friend class base::RefCounted<CompositorLock>;
   friend class Compositor;
 
   explicit CompositorLock(Compositor* compositor);
   ~CompositorLock();
@@ skipping 92 matching lines @@
   // Compositor does not own observers. It is the responsibility of the
   // observer to remove itself when it is done observing.
   void AddObserver(CompositorObserver* observer);
   void RemoveObserver(CompositorObserver* observer);
   bool HasObserver(const CompositorObserver* observer) const;
 
   void AddAnimationObserver(CompositorAnimationObserver* observer);
   void RemoveAnimationObserver(CompositorAnimationObserver* observer);
   bool HasAnimationObserver(const CompositorAnimationObserver* observer) const;
 
+  // Change the timeout behavior for all future locks that are created. Locks
+  // should time out if there is an expectation that the compositor will be
+  // responsive.
+  void SetLocksWillTimeOut(bool locks_will_time_out) {
+    locks_will_time_out_ = locks_will_time_out;
+  }
+
   // Creates a compositor lock. Returns NULL if it is not possible to lock at
   // this time (i.e. we're waiting to complete a previous unlock).
   scoped_refptr<CompositorLock> GetCompositorLock();
 
   // Internal functions, called back by command-buffer contexts on swap buffer
   // events.
 
   // Signals swap has been posted.
   void OnSwapBuffersPosted();
 
@@ skipping 73 matching lines @@
   // 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.
   float device_scale_factor_;
 
   int last_started_frame_;
   int last_ended_frame_;
 
-  bool disable_schedule_composite_;
-
+  bool locks_will_time_out_;
   CompositorLock* compositor_lock_;
 
   LayerAnimatorCollection layer_animator_collection_;
 
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_