cc: Split animating and drawing into separate actions

cc/scheduler/scheduler_state_machine.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_state_machine.h"
 
 #include "base/debug/trace_event.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
 #include "ui/gfx/frame_time.h"
 
 namespace cc {
 
 SchedulerStateMachine::SchedulerStateMachine(const SchedulerSettings& settings)
     : settings_(settings),
       output_surface_state_(OUTPUT_SURFACE_LOST),
       begin_impl_frame_state_(BEGIN_IMPL_FRAME_STATE_IDLE),
       commit_state_(COMMIT_STATE_IDLE),
       forced_redraw_state_(FORCED_REDRAW_STATE_IDLE),
       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),
       manage_tiles_funnel_(0),
       consecutive_checkerboard_animations_(0),
       needs_redraw_(false),
+      needs_animate_(false),
       needs_manage_tiles_(false),
       swap_used_incomplete_tile_(false),
       needs_commit_(false),
       inside_poll_for_anticipated_draw_triggers_(false),
       visible_(false),
       can_start_(false),
       can_draw_(false),
       has_pending_tree_(false),
       pending_tree_is_ready_for_activation_(false),
       active_tree_needs_first_draw_(false),
       draw_if_possible_failed_(false),
       did_create_and_initialize_first_output_surface_(false),
       smoothness_takes_priority_(false),
       skip_next_begin_main_frame_to_reduce_latency_(false),
       skip_begin_main_frame_to_reduce_latency_(false),
       continuous_painting_(false),
-      needs_back_to_back_readback_(false) {}
+      needs_back_to_back_readback_(false) {
+}
 
 const char* SchedulerStateMachine::OutputSurfaceStateToString(
     OutputSurfaceState state) {
   switch (state) {
     case OUTPUT_SURFACE_ACTIVE:
       return "OUTPUT_SURFACE_ACTIVE";
     case OUTPUT_SURFACE_LOST:
       return "OUTPUT_SURFACE_LOST";
     case OUTPUT_SURFACE_CREATING:
       return "OUTPUT_SURFACE_CREATING";
@@ skipping 76 matching lines @@
       return "FORCED_REDRAW_STATE_WAITING_FOR_DRAW";
   }
   NOTREACHED();
   return "???";
 }
 
 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:
       return "ACTION_COMMIT";
     case ACTION_UPDATE_VISIBLE_TILES:
       return "ACTION_UPDATE_VISIBLE_TILES";
     case ACTION_ACTIVATE_PENDING_TREE:
       return "ACTION_ACTIVATE_PENDING_TREE";
     case ACTION_DRAW_AND_SWAP_IF_POSSIBLE:
       return "ACTION_DRAW_AND_SWAP_IF_POSSIBLE";
@@ skipping 53 matching lines @@
   timestamps_state->SetDouble(
       "6_deadline",
       (begin_impl_frame_args_.deadline - base::TimeTicks()).InMicroseconds() /
           1000.0L);
   state->Set("major_timestamps_in_ms", timestamps_state.release());
 
   scoped_ptr<base::DictionaryValue> minor_state(new base::DictionaryValue);
   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(
       "last_frame_number_begin_main_frame_sent",
       last_frame_number_begin_main_frame_sent_);
   minor_state->SetInteger(
       "last_frame_number_update_visible_tiles_was_called",
       last_frame_number_update_visible_tiles_was_called_);
 
   minor_state->SetInteger("manage_tiles_funnel", manage_tiles_funnel_);
   minor_state->SetInteger("consecutive_checkerboard_animations",
                           consecutive_checkerboard_animations_);
   minor_state->SetBoolean("needs_redraw", needs_redraw_);
+  minor_state->SetBoolean("needs_animate_", needs_animate_);
   minor_state->SetBoolean("needs_manage_tiles", needs_manage_tiles_);
   minor_state->SetBoolean("swap_used_incomplete_tile",
                           swap_used_incomplete_tile_);
   minor_state->SetBoolean("needs_commit", needs_commit_);
   minor_state->SetBoolean("visible", visible_);
   minor_state->SetBoolean("can_start", can_start_);
   minor_state->SetBoolean("can_draw", can_draw_);
   minor_state->SetBoolean("has_pending_tree", has_pending_tree_);
   minor_state->SetBoolean("pending_tree_is_ready_for_activation",
                           pending_tree_is_ready_for_activation_);
@@ skipping 172 matching lines @@
 
   // If the last swap drew with checkerboard or missing tiles, we should
   // poll for any new visible tiles so we can be notified to draw again
   // when there are.
   if (swap_used_incomplete_tile_)
     return true;
 
   return false;
 }
 
+bool SchedulerStateMachine::ShouldAnimate() const {
+  if (!can_draw_)
+    return false;
+
+  if (last_frame_number_animate_performed_ == current_frame_number_)
+    return false;
+
+  if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING &&
+      begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
+    return false;
+
+  return needs_redraw_ || needs_animate_;
+}
+
 bool SchedulerStateMachine::ShouldSendBeginMainFrame() const {
   if (!needs_commit_)
     return false;
 
   // Only send BeginMainFrame when there isn't another commit pending already.
   if (commit_state_ != COMMIT_STATE_IDLE)
     return false;
 
   // Don't send BeginMainFrame early if we are prioritizing the active tree
   // because of smoothness_takes_priority.
@@ skipping 79 matching lines @@
   return needs_manage_tiles_;
 }
 
 SchedulerStateMachine::Action SchedulerStateMachine::NextAction() const {
   if (ShouldUpdateVisibleTiles())
     return ACTION_UPDATE_VISIBLE_TILES;
   if (ShouldActivatePendingTree())
     return ACTION_ACTIVATE_PENDING_TREE;
   if (ShouldCommit())
     return ACTION_COMMIT;
+  if (ShouldAnimate())
+    return ACTION_ANIMATE;
   if (ShouldDraw()) {
     if (readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK)
       return ACTION_DRAW_AND_READBACK;
     else if (PendingDrawsShouldBeAborted())
       return ACTION_DRAW_AND_SWAP_ABORT;
     else if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
       return ACTION_DRAW_AND_SWAP_FORCED;
     else
       return ACTION_DRAW_AND_SWAP_IF_POSSIBLE;
   }
@@ skipping 20 matching lines @@
 
     case ACTION_UPDATE_VISIBLE_TILES:
       last_frame_number_update_visible_tiles_was_called_ =
           current_frame_number_;
       return;
 
     case ACTION_ACTIVATE_PENDING_TREE:
       UpdateStateOnActivation();
       return;
 
+    case ACTION_ANIMATE:
+      last_frame_number_animate_performed_ = current_frame_number_;
+      needs_animate_ = false;
+      // TODO(skyostil): Instead of assuming this, require the client to tell
+      // us.
+      SetNeedsRedraw();
+      return;
+
     case ACTION_SEND_BEGIN_MAIN_FRAME:
       DCHECK(!has_pending_tree_ ||
              settings_.main_frame_before_activation_enabled);
       DCHECK(!active_tree_needs_first_draw_ ||
              settings_.main_frame_before_draw_enabled);
       DCHECK(visible_ ||
              readback_state_ == READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME);
       commit_state_ = COMMIT_STATE_BEGIN_MAIN_FRAME_SENT;
       needs_commit_ = false;
       if (readback_state_ == READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME)
@@ skipping 245 matching lines @@
   // There's no need to produce frames if we are not visible.
   if (!visible_)
     return false;
 
   // We need to draw a more complete frame than we did the last BeginImplFrame,
   // so request another BeginImplFrame in anticipation that we will have
   // additional visible tiles.
   if (swap_used_incomplete_tile_)
     return true;
 
+  if (needs_animate_)

[brianderson, 2014/04/18 01:10:54]

If the BeginFrame is needed to advance the animation, should we rename this
method to just BeginFrameNeeded?

If it's not, I feel like this if should go into ProactiveBeginFrameWanted.

[Sami, 2014/04/22 10:34:33]

It feels like an animation request is a stronger signal that we're about to draw
than what we currently have in ProactiveBeginFrameWanted. Also, I think we need
to have the check here anyway for synchronous compositing.

How about BeginFrameNeededToAnimateOrDraw -- since we already have a more
generic BeginFrameNeeded?

+    return true;
+
   return needs_redraw_;
 }
 
 // These are cases where we are very likely to draw soon, but might not
 // actually have a new frame to draw when we receive the next BeginImplFrame.
 // Proactively requesting the BeginImplFrame helps hide the round trip latency
 // of the SetNeedsBeginFrame request that has to go to the Browser.
 bool SchedulerStateMachine::ProactiveBeginFrameWanted() const {
   // The output surface is the provider of BeginImplFrames,
   // so we are not going to get them even if we ask for them.
@@ skipping 145 matching lines @@
 void SchedulerStateMachine::DidLeavePollForAnticipatedDrawTriggers() {
   inside_poll_for_anticipated_draw_triggers_ = false;
 }
 
 void SchedulerStateMachine::SetVisible(bool visible) { visible_ = visible; }
 
 void SchedulerStateMachine::SetCanDraw(bool can_draw) { can_draw_ = can_draw; }
 
 void SchedulerStateMachine::SetNeedsRedraw() { needs_redraw_ = true; }
 
+void SchedulerStateMachine::SetNeedsAnimate() {
+  needs_animate_ = true;
+}
+
 void SchedulerStateMachine::SetNeedsManageTiles() {
   if (!needs_manage_tiles_) {
     TRACE_EVENT0("cc",
                  "SchedulerStateMachine::SetNeedsManageTiles");
     needs_manage_tiles_ = true;
   }
 }
 
 void SchedulerStateMachine::SetSwapUsedIncompleteTile(
     bool used_incomplete_tile) {
@@ skipping 152 matching lines @@
     case OUTPUT_SURFACE_ACTIVE:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION:
       return true;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace cc