cc: Split animating and drawing into separate actions

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 2bbf2563264bb1365654663e8d13435346357137..25ac240249f006372e6322ec8590e0c2087ccf39 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -23,6 +23,7 @@ SchedulerStateMachine::SchedulerStateMachine(const SchedulerSettings& settings)
       readback_state_(READBACK_STATE_IDLE),
       commit_count_(0),
       current_frame_number_(0),
+      last_frame_number_animate_performed_(-1),
       last_frame_number_swap_performed_(-1),
       last_frame_number_begin_main_frame_sent_(-1),
       last_frame_number_update_visible_tiles_was_called_(-1),
@@ -154,6 +155,8 @@ const char* SchedulerStateMachine::ActionToString(Action action) {
   switch (action) {
     case ACTION_NONE:
       return "ACTION_NONE";
+    case ACTION_ANIMATE:
+      return "ACTION_ANIMATE";
     case ACTION_SEND_BEGIN_MAIN_FRAME:
       return "ACTION_SEND_BEGIN_MAIN_FRAME";
     case ACTION_COMMIT:
@@ -235,6 +238,8 @@ scoped_ptr<base::Value> SchedulerStateMachine::AsValue() const  {
   minor_state->SetInteger("commit_count", commit_count_);
   minor_state->SetInteger("current_frame_number", current_frame_number_);
 
+  minor_state->SetInteger("last_frame_number_animate_performed",
+                          last_frame_number_animate_performed_);
   minor_state->SetInteger("last_frame_number_swap_performed",
                           last_frame_number_swap_performed_);
   minor_state->SetInteger(
@@ -455,6 +460,16 @@ bool SchedulerStateMachine::ShouldUpdateVisibleTiles() const {
   return false;
 }
 
+bool SchedulerStateMachine::ShouldAnimate() const {
+  if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING)
+    return false;
+
+  if (last_frame_number_animate_performed_ == current_frame_number_)
+    return false;
+
+  return true;
+}
+
 bool SchedulerStateMachine::ShouldSendBeginMainFrame() const {
   if (!needs_commit_)
     return false;
@@ -568,6 +583,8 @@ SchedulerStateMachine::Action SchedulerStateMachine::NextAction() const {
   }
   if (ShouldManageTiles())
     return ACTION_MANAGE_TILES;
+  if (ShouldAnimate())
+    return ACTION_ANIMATE;
   if (ShouldSendBeginMainFrame())
     return ACTION_SEND_BEGIN_MAIN_FRAME;
   if (ShouldBeginOutputSurfaceCreation())
@@ -601,6 +618,10 @@ void SchedulerStateMachine::UpdateState(Action action) {
       UpdateStateOnActivation();
       return;
 
+    case ACTION_ANIMATE:
+      last_frame_number_animate_performed_ = current_frame_number_;
+      return;
+
     case ACTION_SEND_BEGIN_MAIN_FRAME:
       DCHECK(!has_pending_tree_ ||
              settings_.main_frame_before_activation_enabled);