cc: Add scheduler support for invalidating content on impl thread.

cc/scheduler/scheduler.h

 // Copyright 2011 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_SCHEDULER_SCHEDULER_H_
 #define CC_SCHEDULER_SCHEDULER_H_
 
 #include <deque>
 #include <memory>
 #include <string>
@@ skipping 27 matching lines @@
   virtual void WillBeginImplFrame(const BeginFrameArgs& args) = 0;
   virtual void ScheduledActionSendBeginMainFrame(
       const BeginFrameArgs& args) = 0;
   virtual DrawResult ScheduledActionDrawIfPossible() = 0;
   virtual DrawResult ScheduledActionDrawForced() = 0;
   virtual void ScheduledActionCommit() = 0;
   virtual void ScheduledActionActivateSyncTree() = 0;
   virtual void ScheduledActionBeginCompositorFrameSinkCreation() = 0;
   virtual void ScheduledActionPrepareTiles() = 0;
   virtual void ScheduledActionInvalidateCompositorFrameSink() = 0;
+  virtual void ScheduledActionPerformImplSideInvalidation() = 0;

[sunnyps, 2017/02/14 21:40:18]

nit/bikeshed: ScheduledActionInvalidateActiveTree?

[Khushal, 2017/02/15 00:56:33]

Hmmm, given that in the default case we actually create a pending tree to
invalidate on the active tree, I don't know if this makes it any clearer...

   virtual void DidFinishImplFrame() = 0;
   virtual void SendBeginMainFrameNotExpectedSoon() = 0;
 
  protected:
   virtual ~SchedulerClient() {}
 };
 
 class CC_EXPORT Scheduler : public BeginFrameObserverBase {
  public:
   Scheduler(SchedulerClient* client,
@@ skipping 24 matching lines @@
 
   void SetNeedsBeginMainFrame();
   // Requests a single impl frame (after the current frame if there is one
   // active).
   void SetNeedsOneBeginImplFrame();
 
   void SetNeedsRedraw();
 
   void SetNeedsPrepareTiles();
 
+  // Requests a pending tree should be created to invalidate content on the impl
+  // thread, after the current tree is activated, if any. If the request
+  // necessitates creating a pending tree only for impl-side invalidations, the
+  // |client_| is informed to perform this action using
+  // ScheduledActionRunImplSideInvalidation.
+  // If ScheduledActionCommit is performed, the impl-side invalidations should
+  // be merged with the main frame and the request is assumed to be completed.
+  void SetNeedsImplSideInvalidation();
+
   // Drawing should result in submitting a CompositorFrame to the
   // CompositorFrameSink and then calling this.
   void DidSubmitCompositorFrame();
   // The CompositorFrameSink acks when it is ready for a new frame which
   // should result in this getting called to unblock the next draw.
   void DidReceiveCompositorFrameAck();
 
   void SetTreePrioritiesAndScrollState(TreePriority tree_priority,
                                        ScrollHandlerState scroll_handler_state);
 
@@ skipping 102 matching lines @@
   }
 
   base::WeakPtrFactory<Scheduler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_H_