cc: Make PrepareToDraw return an enum for why it aborts

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 <string>
 
 #include "base/basictypes.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "cc/base/cc_export.h"
 #include "cc/output/begin_frame_args.h"
+#include "cc/scheduler/draw_swap_readback_result.h"
 #include "cc/scheduler/scheduler_settings.h"
 #include "cc/scheduler/scheduler_state_machine.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
 
 class Thread;
 
-struct DrawSwapReadbackResult {
-  DrawSwapReadbackResult()
-      : did_draw(false), did_swap(false), did_readback(false) {}
-  DrawSwapReadbackResult(bool did_draw, bool did_swap, bool did_readback)
-      : did_draw(did_draw), did_swap(did_swap), did_readback(did_readback) {}
-  bool did_draw;
-  bool did_swap;
-  bool did_readback;
-};
-
 class SchedulerClient {
  public:
   virtual void SetNeedsBeginImplFrame(bool enable) = 0;
   virtual void ScheduledActionSendBeginMainFrame() = 0;
   virtual DrawSwapReadbackResult ScheduledActionDrawAndSwapIfPossible() = 0;
   virtual DrawSwapReadbackResult ScheduledActionDrawAndSwapForced() = 0;
   virtual DrawSwapReadbackResult ScheduledActionDrawAndReadback() = 0;
   virtual void ScheduledActionCommit() = 0;
   virtual void ScheduledActionUpdateVisibleTiles() = 0;
   virtual void ScheduledActionActivatePendingTree() = 0;
@@ skipping 114 matching lines @@
   SchedulerStateMachine::Action inside_action_;
 
   base::WeakPtrFactory<Scheduler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_H_