cc: Simplify and rename MainThreadIsInHighLatency logic

cc/scheduler/scheduler_state_machine.cc

Index: cc/scheduler/scheduler_state_machine.cc
diff --git a/cc/scheduler/scheduler_state_machine.cc b/cc/scheduler/scheduler_state_machine.cc
index ad27328ec4bd2e967426b4eeade1bb3e6fecfa15..f7e4b24bf5aface96a3237157683a72a04e57ebf 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -47,6 +47,7 @@ SchedulerStateMachine::SchedulerStateMachine(const SchedulerSettings& settings)
       active_tree_needs_first_draw_(false),
       did_create_and_initialize_first_output_surface_(false),
       impl_latency_takes_priority_(false),
+      main_thread_missed_last_deadline_(false),
       skip_next_begin_main_frame_to_reduce_latency_(false),
       continuous_painting_(false),
       children_need_begin_frames_(false),
@@ -237,8 +238,8 @@ void SchedulerStateMachine::AsValueInto(
                     did_create_and_initialize_first_output_surface_);
   state->SetBoolean("impl_latency_takes_priority",
                     impl_latency_takes_priority_);
-  state->SetBoolean("main_thread_is_in_high_latency_mode",
-                    MainThreadIsInHighLatencyMode());
+  state->SetBoolean("main_thread_missed_last_deadline",
+                    main_thread_missed_last_deadline_);
   state->SetBoolean("skip_next_begin_main_frame_to_reduce_latency",
                     skip_next_begin_main_frame_to_reduce_latency_);
   state->SetBoolean("continuous_painting", continuous_painting_);
@@ -879,6 +880,11 @@ void SchedulerStateMachine::OnBeginImplFrameIdle() {
   begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_IDLE;
 
   skip_next_begin_main_frame_to_reduce_latency_ = false;
+
+  // If a new or undrawn active tree is pending after the deadline,
+  // then the main thread is in a high latency mode.
+  main_thread_missed_last_deadline_ =
+      CommitPending() || has_pending_tree_ || active_tree_needs_first_draw_;
 }
 
 SchedulerStateMachine::BeginImplFrameDeadlineMode
@@ -939,52 +945,23 @@ bool SchedulerStateMachine::ShouldTriggerBeginImplFrameDeadlineImmediately()
   return false;
 }
 
-bool SchedulerStateMachine::MainThreadIsInHighLatencyMode() const {
-  // If a commit is pending before the previous commit has been drawn, we
-  // are definitely in a high latency mode.
-  if (CommitPending() && (active_tree_needs_first_draw_ || has_pending_tree_))
-    return true;
-
-  // If we just sent a BeginMainFrame and haven't hit the deadline yet, the main
-  // thread is in a low latency mode.
-  if (send_begin_main_frame_funnel_ &&
-      (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING ||
-       begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME))
-    return false;
-
-  // If there's a commit in progress it must either be from the previous frame
-  // or it started after the impl thread's deadline. In either case the main
-  // thread is in high latency mode.
-  if (CommitPending())
-    return true;
-
-  // Similarly, if there's a pending tree the main thread is in high latency
-  // mode, because either
-  //   it's from the previous frame
-  // or
-  //   we're currently drawing the active tree and the pending tree will thus
-  //   only be drawn in the next frame.
-  if (has_pending_tree_)
-    return true;
-
-  if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE) {
-    // Even if there's a new active tree to draw at the deadline or we've just
-    // swapped it, it may have been triggered by a previous BeginImplFrame, in
-    // which case the main thread is in a high latency mode.
-    return (active_tree_needs_first_draw_ || did_perform_swap_in_last_draw_) &&
-           !send_begin_main_frame_funnel_;
-  }
-
-  // If the active tree needs its first draw in any other state, we know the
-  // main thread is in a high latency mode.
-  return active_tree_needs_first_draw_;
+bool SchedulerStateMachine::main_thread_missed_last_deadline() const {
+  return main_thread_missed_last_deadline_;
 }
 
 bool SchedulerStateMachine::SwapThrottled() const {
   return pending_swaps_ >= max_pending_swaps_;
 }
 
-void SchedulerStateMachine::SetVisible(bool visible) { visible_ = visible; }
+void SchedulerStateMachine::SetVisible(bool visible) {
+  if (visible_ == visible)
+    return;
+
+  if (visible)
+    main_thread_missed_last_deadline_ = false;
+
+  visible_ = visible;
+}
 
 void SchedulerStateMachine::SetCanDraw(bool can_draw) { can_draw_ = can_draw; }
 
@@ -1145,6 +1122,7 @@ void SchedulerStateMachine::DidCreateAndInitializeOutputSurface() {
   did_create_and_initialize_first_output_surface_ = true;
   pending_swaps_ = 0;
   swaps_with_current_output_surface_ = 0;
+  main_thread_missed_last_deadline_ = false;

[sunnyps, 2015/07/13 20:03:09]

It looks like we need to set main_thread_missed_last_deadline_ to false whenever
NeedsBeginFrames goes from false to true. I need to do something similar in an
upcoming CL for a webview bug.

 }
 
 void SchedulerStateMachine::NotifyBeginMainFrameStarted() {