cc: Implement deadine scheduling disabled by default

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index ecb47a182ceb7b4f757b6b6860b75a7d00a3b515..a9672e06e2bcc28bf11786ffb35b2508d06b6736 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -4,6 +4,7 @@
 
 #include "cc/scheduler/scheduler.h"
 
+#include <algorithm>
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ -18,11 +19,12 @@ Scheduler::Scheduler(SchedulerClient* client,
       weak_factory_(this),
       last_set_needs_begin_frame_(false),
       has_pending_begin_frame_(false),
-      safe_to_expect_begin_frame_(false),
+      safe_to_expect_begin_frame_(
+          !scheduler_settings.use_begin_frame_workaround_for_crbug_249806),
       state_machine_(scheduler_settings),
       inside_process_scheduled_actions_(false) {
   DCHECK(client_);
-  DCHECK(!state_machine_.BeginFrameNeededToDrawByImplThread());
+  DCHECK(!state_machine_.BeginFrameNeededByImplThread());
 }
 
 Scheduler::~Scheduler() {
@@ -79,6 +81,9 @@ void Scheduler::FinishCommit() {
   TRACE_EVENT0("cc", "Scheduler::FinishCommit");
   state_machine_.FinishCommit();
   ProcessScheduledActions();
+
+  if (state_machine_.ShouldTriggerBeginFrameDeadlineEarly())
+    PostBeginFrameDeadline(base::TimeTicks());
 }
 
 void Scheduler::BeginFrameAbortedByMainThread(bool did_handle) {
@@ -89,6 +94,8 @@ void Scheduler::BeginFrameAbortedByMainThread(bool did_handle) {
 
 void Scheduler::DidLoseOutputSurface() {
   TRACE_EVENT0("cc", "Scheduler::DidLoseOutputSurface");
+  begin_frame_deadline_closure_.Cancel();
+  has_pending_begin_frame_ = false;
   state_machine_.DidLoseOutputSurface();
   ProcessScheduledActions();
 }
@@ -96,9 +103,11 @@ void Scheduler::DidLoseOutputSurface() {
 void Scheduler::DidCreateAndInitializeOutputSurface() {
   TRACE_EVENT0("cc", "Scheduler::DidCreateAndInitializeOutputSurface");
   state_machine_.DidCreateAndInitializeOutputSurface();
+  begin_frame_deadline_closure_.Cancel();
   has_pending_begin_frame_ = false;
   last_set_needs_begin_frame_ = false;
-  safe_to_expect_begin_frame_ = false;
+  safe_to_expect_begin_frame_ =
+      !settings_.use_begin_frame_workaround_for_crbug_249806;
   ProcessScheduledActions();
 }
 
@@ -109,12 +118,11 @@ base::TimeTicks Scheduler::AnticipatedDrawTime() {
       last_begin_frame_args_.interval <= base::TimeDelta())
     return base::TimeTicks();
 
-  // TODO(brianderson): Express this in terms of the deadline.
   base::TimeTicks now = base::TimeTicks::Now();
-  int64 intervals = 1 + ((now - last_begin_frame_args_.frame_time) /
-                         last_begin_frame_args_.interval);
-  return last_begin_frame_args_.frame_time +
-      (last_begin_frame_args_.interval * intervals);
+  base::TimeTicks timebase = std::max(last_begin_frame_args_.frame_time,
+                                      last_begin_frame_args_.deadline);
+  int64 intervals = 1 + ((now - timebase) / last_begin_frame_args_.interval);
+  return timebase + (last_begin_frame_args_.interval * intervals);
 }
 
 base::TimeTicks Scheduler::LastBeginFrameOnImplThreadTime() {
@@ -124,41 +132,37 @@ base::TimeTicks Scheduler::LastBeginFrameOnImplThreadTime() {
 void Scheduler::SetupNextBeginFrameIfNeeded() {
   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;
+      state_machine_.ProactiveBeginFrameWantedByImplThread();
+
+  // We want to avoid proactive begin frames with the synchronous
+  // compositor because every SetNeedsBeginFrame will force a redraw.
+  bool needs_begin_frame =
+      needs_begin_frame_to_draw || proactive_begin_frame_wanted;
+
+  bool should_call_set_needs_begin_frame =
+      // The synchronous renderer compositor needs immediate enables/disables.
+      (settings_.using_synchronous_renderer_compositor &&
+       needs_begin_frame != last_set_needs_begin_frame_) ||
+      // Always request the BeginFrame immediately if it wasn't needed before.
+      (needs_begin_frame && !last_set_needs_begin_frame_) ||
+      // Only disable the BeginFrame after a BeginFrame where we didn't swap.
+      (!needs_begin_frame && last_set_needs_begin_frame_ &&
+       has_pending_begin_frame_ && !state_machine_.InsideBeginFrame()) ||
+      // We did not draw and swap this BeginFrame,
+      // so we need to explicitly request another BeginFrame.
+      (needs_begin_frame && has_pending_begin_frame_ &&
+       !state_machine_.InsideBeginFrame());
 
   if (needs_begin_frame_to_draw)
     safe_to_expect_begin_frame_ = true;
 
-  // 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_)) {
+  if (should_call_set_needs_begin_frame) {
     has_pending_begin_frame_ = false;
     client_->SetNeedsBeginFrameOnImplThread(needs_begin_frame);
     if (safe_to_expect_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);
-    return;
-  }
 }
 
 void Scheduler::BeginFrame(const BeginFrameArgs& args) {
@@ -167,9 +171,53 @@ void Scheduler::BeginFrame(const BeginFrameArgs& args) {
   has_pending_begin_frame_ = true;
   safe_to_expect_begin_frame_ = true;
   last_begin_frame_args_ = args;
-  state_machine_.DidEnterBeginFrame(args);
+  last_begin_frame_args_.deadline -= client_->DrawDurationEstimate();
+  state_machine_.OnBeginFrame(last_begin_frame_args_);
+  ProcessScheduledActions();
+
+  if (settings_.using_synchronous_renderer_compositor) {
+    // The synchronous renderer compositor has to make it's GL calls
+    // within this call to BeginFrame.
+    // TODO(brianderson): Have the OutputSurface initiate the deadline tasks
+    // so the sychronous renderer compoistor can take advantage of splitting
+    // up the BeginFrame and deadline as well.
+    OnBeginFrameDeadline();
+  } else if (!settings_.deadline_scheduling_enabled) {
+    // We emulate the old non-deadline scheduler here by posting the
+    // deadline task without any delay.
+    PostBeginFrameDeadline(base::TimeTicks());
+  } else if (state_machine_.ShouldTriggerBeginFrameDeadlineEarly()) {
+    // We are ready to draw a new active tree immediately.
+    PostBeginFrameDeadline(base::TimeTicks());
+  } else if (state_machine_.needs_redraw()) {
+    // We have an animation or fast input path on the impl thread that wants
+    // to draw, so don't wait too long for a new active tree.
+    PostBeginFrameDeadline(last_begin_frame_args_.deadline);
+  } else {
+    // The impl thread doesn't have anything it wants to draw and we are just
+    // waiting for a new active tree, so post the deadline for the next
+    // expected BeginFrame start.
+    // TODO(brianderson): Handle long deadlines (that are past the next frame's
+    // frame time) properly instead of using this hack.
+    PostBeginFrameDeadline(last_begin_frame_args_.frame_time +
+                           last_begin_frame_args_.interval);
+  }
+}
+
+void Scheduler::PostBeginFrameDeadline(base::TimeTicks deadline) {
+  begin_frame_deadline_closure_.Cancel();
+  begin_frame_deadline_closure_.Reset(
+      base::Bind(&Scheduler::OnBeginFrameDeadline, weak_factory_.GetWeakPtr()));
+  client_->PostBeginFrameDeadline(begin_frame_deadline_closure_.callback(),
+                                  deadline);
+}
+
+void Scheduler::OnBeginFrameDeadline() {
+  TRACE_EVENT0("cc", "Scheduler::OnBeginFrameDeadline");
+  begin_frame_deadline_closure_.Cancel();
+  state_machine_.OnBeginFrameDeadline();
   ProcessScheduledActions();
-  state_machine_.DidLeaveBeginFrame();
+  client_->DidBeginFrameDeadlineOnImplThread();
 }
 
 void Scheduler::DrawAndSwapIfPossible() {
@@ -240,6 +288,7 @@ void Scheduler::ProcessScheduledActions() {
     }
   } while (action != SchedulerStateMachine::ACTION_NONE);
 
+  state_machine_.AdvanceBeginFrameStateWhenNoActionsRemain();
   SetupNextBeginFrameIfNeeded();
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 }