cc: Always use SetNeedsBeginFrame to request the next BeginFrame

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index ebdc289b18e50082e00ff9cac20698d227e00f0b..376ead2528eb1564bdcf7acc6dfdfe243d4e2ffc 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -17,7 +17,6 @@ Scheduler::Scheduler(SchedulerClient* client,
       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_);
@@ -95,7 +94,6 @@ void Scheduler::DidLoseOutputSurface() {
 void Scheduler::DidCreateAndInitializeOutputSurface() {
   TRACE_EVENT0("cc", "Scheduler::DidCreateAndInitializeOutputSurface");
   state_machine_.DidCreateAndInitializeOutputSurface();
-  has_pending_begin_frame_ = false;
   last_set_needs_begin_frame_ = false;
   ProcessScheduledActions();
 }
@@ -130,29 +128,18 @@ void Scheduler::SetupNextBeginFrameIfNeeded() {
       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 &&
@@ -173,8 +160,7 @@ void Scheduler::SetupNextBeginFrameIfNeeded() {
 
 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();
@@ -191,14 +177,10 @@ 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() {