cc: Always use SetNeedsBeginFrame to request the next BeginFrame

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"
 
 namespace cc {
 
 Scheduler::Scheduler(SchedulerClient* client,
                      const SchedulerSettings& scheduler_settings)
     : settings_(scheduler_settings),
       client_(client),
       weak_factory_(this),
       last_set_needs_begin_frame_(false),
-      has_pending_begin_frame_(false),
       state_machine_(scheduler_settings),
       inside_process_scheduled_actions_(false) {
   DCHECK(client_);
   DCHECK(!state_machine_.BeginFrameNeededToDrawByImplThread());
 }
 
 Scheduler::~Scheduler() {
   client_->SetNeedsBeginFrameOnImplThread(false);
 }
 
@@ skipping 57 matching lines @@
 
 void Scheduler::DidLoseOutputSurface() {
   TRACE_EVENT0("cc", "Scheduler::DidLoseOutputSurface");
   state_machine_.DidLoseOutputSurface();
   ProcessScheduledActions();
 }
 
 void Scheduler::DidCreateAndInitializeOutputSurface() {
   TRACE_EVENT0("cc", "Scheduler::DidCreateAndInitializeOutputSurface");
   state_machine_.DidCreateAndInitializeOutputSurface();
-  has_pending_begin_frame_ = false;
   last_set_needs_begin_frame_ = false;
   ProcessScheduledActions();
 }
 
 base::TimeTicks Scheduler::AnticipatedDrawTime() {
   TRACE_EVENT0("cc", "Scheduler::AnticipatedDrawTime");
 
   if (!last_set_needs_begin_frame_ ||
       last_begin_frame_args_.interval <= base::TimeDelta())
     return base::TimeTicks();
@@ skipping 14 matching lines @@
   bool needs_begin_frame_to_draw =
       state_machine_.BeginFrameNeededToDrawByImplThread();
   // We want to avoid proactive begin frames with the synchronous compositor
   // because every SetNeedsBeginFrame will force a redraw.
   bool proactive_begin_frame_wanted =
       state_machine_.ProactiveBeginFrameWantedByImplThread() &&
       !settings_.using_synchronous_renderer_compositor &&
       settings_.throttle_frame_production;
   bool needs_begin_frame = needs_begin_frame_to_draw ||
                            proactive_begin_frame_wanted;
-  bool immediate_disables_needed =
-      settings_.using_synchronous_renderer_compositor;
 
-  // Determine if we need BeginFrame notifications.
-  // If we do, always request the BeginFrame immediately.
-  // If not, only disable on the next BeginFrame to avoid unnecessary toggles.
-  // The synchronous renderer compositor requires immediate disables though.
-  if ((needs_begin_frame ||
-       state_machine_.inside_begin_frame() ||
-       immediate_disables_needed) &&
-      (needs_begin_frame != last_set_needs_begin_frame_)) {
-    has_pending_begin_frame_ = false;
+  bool should_call_set_needs_begin_frame =
+      // Always request the BeginFrame immediately if it wasn't needed before.
+      (needs_begin_frame && !last_set_needs_begin_frame_) ||
+      // We always need to explicitly request our next BeginFrame.
+      state_machine_.inside_begin_frame();
+
+  if (should_call_set_needs_begin_frame) {
     client_->SetNeedsBeginFrameOnImplThread(needs_begin_frame);
     last_set_needs_begin_frame_ = needs_begin_frame;
   }
 
-  // Request another BeginFrame if we haven't drawn for now until we have
-  // deadlines implemented.
-  if (state_machine_.inside_begin_frame() && has_pending_begin_frame_) {
-    has_pending_begin_frame_ = false;
-    client_->SetNeedsBeginFrameOnImplThread(true);
-  }
-
   // Setup PollForAnticipatedDrawTriggers for cases where we want a proactive
   // BeginFrame but aren't requesting one.
   if (!needs_begin_frame &&
       state_machine_.ProactiveBeginFrameWantedByImplThread()) {
     if (poll_for_draw_triggers_closure_.IsCancelled()) {
       poll_for_draw_triggers_closure_.Reset(
           base::Bind(&Scheduler::PollForAnticipatedDrawTriggers,
                      weak_factory_.GetWeakPtr()));
       base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           poll_for_draw_triggers_closure_.callback(),
           last_begin_frame_args_.interval);
     }
   } else {
     poll_for_draw_triggers_closure_.Cancel();
   }
 }
 
 void Scheduler::BeginFrame(const BeginFrameArgs& args) {
   TRACE_EVENT0("cc", "Scheduler::BeginFrame");
-  DCHECK(!has_pending_begin_frame_);
-  has_pending_begin_frame_ = true;
+  DCHECK(!state_machine_.inside_begin_frame());
   last_begin_frame_args_ = args;
   state_machine_.DidEnterBeginFrame(args);
   ProcessScheduledActions();
   state_machine_.DidLeaveBeginFrame();
 }
 
 void Scheduler::PollForAnticipatedDrawTriggers() {
   TRACE_EVENT0("cc", "Scheduler::PollForAnticipatedDrawTriggers");
   state_machine_.PollForAnticipatedDrawTriggers();
   ProcessScheduledActions();
 }
 
 void Scheduler::DrawAndSwapIfPossible() {
   DrawSwapReadbackResult result =
       client_->ScheduledActionDrawAndSwapIfPossible();
   state_machine_.DidDrawIfPossibleCompleted(result.did_draw);
-  if (result.did_swap)
-    has_pending_begin_frame_ = false;
 }
 
 void Scheduler::DrawAndSwapForced() {
-  DrawSwapReadbackResult result = client_->ScheduledActionDrawAndSwapForced();
-  if (result.did_swap)
-    has_pending_begin_frame_ = false;
+  client_->ScheduledActionDrawAndSwapForced();
 }
 
 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.
@@ skipping 50 matching lines @@
 
   SetupNextBeginFrameIfNeeded();
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 }
 
 bool Scheduler::WillDrawIfNeeded() const {
   return !state_machine_.PendingDrawsShouldBeAborted();
 }
 
 }  // namespace cc