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::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:
+        client_->ScheduledActionDrawAndReadback();

[danakj, 2013/08/30 15:56:41]

How about a DrawAndReadback() method above that can DCHECK the result values are
as expected?

[brianderson, 2013/09/03 22:41:12]

I avoided checking for success because I read somewhere in the code that the
readback could fail in some cases and that would be ok. Is readback always
expected to succeed? Or did you just want to check that did_readback is true if
the draw succeeded?

+        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