Reland of cc: Remove frame queuing from the scheduler.

cc/scheduler/scheduler_state_machine.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_state_machine.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 349 matching lines @@
 
   // Do not queue too many swaps.
   if (SwapThrottled())
     return false;
 
   // Except for the cases above, do not draw outside of the BeginImplFrame
   // deadline.
   if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
     return false;
 
+  if (wait_for_ready_to_draw_)
+    return false;
+
   // Only handle forced redraws due to timeouts on the regular deadline.
   if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
     return true;
 
   return needs_redraw_;
 }
 
 bool SchedulerStateMachine::ShouldActivatePendingTree() const {
   // There is nothing to activate.
   if (!has_pending_tree_)
@@ skipping 97 matching lines @@
 bool SchedulerStateMachine::ShouldCommit() const {
   if (begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT)
     return false;
 
   // We must not finish the commit until the pending tree is free.
   if (has_pending_tree_) {
     DCHECK(settings_.main_frame_before_activation_enabled);
     return false;
   }
 
+  // Active tree resources might still be in use until the Display draws.
+  if (settings_.commit_to_active_tree && SwapThrottled())
+    return false;
+
   // If we only have an active tree, it is incorrect to replace it
   // before we've drawn it.
   DCHECK(!settings_.commit_to_active_tree || !active_tree_needs_first_draw_);
 
   return true;
 }
 
 bool SchedulerStateMachine::ShouldPrepareTiles() const {
   // PrepareTiles only really needs to be called immediately after commit
   // and then periodically after that. Use a funnel to make sure we average
@@ skipping 525 matching lines @@
 }
 
 void SchedulerStateMachine::SetNeedsOneBeginImplFrame() {
   needs_one_begin_impl_frame_ = true;
 }
 
 void SchedulerStateMachine::NotifyReadyToCommit() {
   DCHECK_EQ(begin_main_frame_state_, BEGIN_MAIN_FRAME_STATE_STARTED)
       << AsValue()->ToString();
   begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT;
-  // In commit_to_active_tree mode, commit should happen right after
-  // BeginFrame, meaning when this function is called, next action should be
-  // commit.
-  if (settings_.commit_to_active_tree)
-    DCHECK(ShouldCommit());
 }
 
 void SchedulerStateMachine::BeginMainFrameAborted(CommitEarlyOutReason reason) {
   DCHECK_EQ(begin_main_frame_state_, BEGIN_MAIN_FRAME_STATE_STARTED);
 
   // If the main thread aborted, it doesn't matter if the  main thread missed
   // the last deadline since it didn't have an update anyway.
   main_thread_missed_last_deadline_ = false;
 
   switch (reason) {
@@ skipping 63 matching lines @@
     case COMPOSITOR_FRAME_SINK_ACTIVE:
     case COMPOSITOR_FRAME_SINK_WAITING_FOR_FIRST_COMMIT:
     case COMPOSITOR_FRAME_SINK_WAITING_FOR_FIRST_ACTIVATION:
       return true;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace cc