cc: Add readback and forced draw states to the Scheduler

cc/scheduler/scheduler.cc

 // 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.
 
 #include "cc/scheduler/scheduler.h"
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "cc/debug/traced_value.h"
@@ skipping 36 matching lines @@
 void Scheduler::NotifyReadyToActivate() {
   state_machine_.NotifyReadyToActivate();
   ProcessScheduledActions();
 }
 
 void Scheduler::SetNeedsCommit() {
   state_machine_.SetNeedsCommit();
   ProcessScheduledActions();
 }
 
-void Scheduler::SetNeedsForcedCommit() {
+void Scheduler::SetNeedsForcedCommitForReadback() {
   state_machine_.SetNeedsCommit();
-  state_machine_.SetNeedsForcedCommit();
+  state_machine_.SetNeedsForcedCommitForReadback();
   ProcessScheduledActions();
 }
 
 void Scheduler::SetNeedsRedraw() {
   state_machine_.SetNeedsRedraw();
   ProcessScheduledActions();
 }
 
 void Scheduler::DidSwapUseIncompleteTile() {
   state_machine_.DidSwapUseIncompleteTile();
   ProcessScheduledActions();
 }
 
-void Scheduler::SetNeedsForcedRedraw() {
-  state_machine_.SetNeedsForcedRedraw();
-  ProcessScheduledActions();
-}
-
 void Scheduler::SetMainThreadNeedsLayerTextures() {
   state_machine_.SetMainThreadNeedsLayerTextures();
   ProcessScheduledActions();
 }
 
 void Scheduler::FinishCommit() {
   TRACE_EVENT0("cc", "Scheduler::FinishCommit");
   state_machine_.FinishCommit();
   ProcessScheduledActions();
 }
@@ skipping 83 matching lines @@
   DCHECK(!has_pending_begin_frame_);
   has_pending_begin_frame_ = true;
   safe_to_expect_begin_frame_ = true;
   last_begin_frame_args_ = args;
   state_machine_.DidEnterBeginFrame(args);
   ProcessScheduledActions();
   state_machine_.DidLeaveBeginFrame();
 }
 
 void Scheduler::DrawAndSwapIfPossible() {
-  ScheduledActionDrawAndSwapResult result =
+  DrawSwapReadbackResult result =
       client_->ScheduledActionDrawAndSwapIfPossible();
   state_machine_.DidDrawIfPossibleCompleted(result.did_draw);
   if (result.did_swap)
     has_pending_begin_frame_ = false;
 }
 
 void Scheduler::DrawAndSwapForced() {
-  ScheduledActionDrawAndSwapResult result =
-      client_->ScheduledActionDrawAndSwapForced();
+  DrawSwapReadbackResult result = client_->ScheduledActionDrawAndSwapForced();
   if (result.did_swap)
     has_pending_begin_frame_ = false;
 }
 
+void Scheduler::DrawAndReadback() {
+  DrawSwapReadbackResult result = client_->ScheduledActionDrawAndReadback();
+  DCHECK(!result.did_swap);
+}
+
 void Scheduler::ProcessScheduledActions() {
   // We do not allow ProcessScheduledActions to be recursive.
   // The top-level call will iteratively execute the next action for us anyway.
   if (inside_process_scheduled_actions_)
     return;
 
   base::AutoReset<bool> mark_inside(&inside_process_scheduled_actions_, true);
 
   SchedulerStateMachine::Action action;
   do {
+    state_machine_.CheckInvariants();
     action = state_machine_.NextAction();
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
                  "SchedulerStateMachine",
                  "state",
                  TracedValue::FromValue(state_machine_.AsValue().release()));
     state_machine_.UpdateState(action);
     switch (action) {
       case SchedulerStateMachine::ACTION_NONE:
         break;
       case SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD:
         client_->ScheduledActionSendBeginFrameToMainThread();
         break;
       case SchedulerStateMachine::ACTION_COMMIT:
         client_->ScheduledActionCommit();
         break;
       case SchedulerStateMachine::ACTION_UPDATE_VISIBLE_TILES:
         client_->ScheduledActionUpdateVisibleTiles();
         break;
       case SchedulerStateMachine::ACTION_ACTIVATE_PENDING_TREE:
         client_->ScheduledActionActivatePendingTree();
         break;
-      case SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE:
+      case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE:
         DrawAndSwapIfPossible();
         break;
-      case SchedulerStateMachine::ACTION_DRAW_FORCED:
+      case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED:
         DrawAndSwapForced();
         break;
       case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_ABORT:
         // No action is actually performed, but this allows the state machine to
         // advance out of its waiting to draw state without actually drawing.
         break;
+      case SchedulerStateMachine::ACTION_DRAW_AND_READBACK:
+        DrawAndReadback();
+        break;
       case SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION:
         client_->ScheduledActionBeginOutputSurfaceCreation();
         break;
       case SchedulerStateMachine::ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD:
         client_->ScheduledActionAcquireLayerTexturesForMainThread();
         break;
     }
   } while (action != SchedulerStateMachine::ACTION_NONE);
 
   SetupNextBeginFrameIfNeeded();
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 }
 
 bool Scheduler::WillDrawIfNeeded() const {
   return !state_machine_.PendingDrawsShouldBeAborted();
 }
 
 }  // namespace cc