CC: Fix missing swap-used-incomplete-tile updates

When we early-out of a frame that has no damage, we didn't
correctly detect if the frame had incomplete tiles. This
patch only updates the flag if a swap actually occurs.

To prevent this kind of bug in the future, this patch
always sets the did-swap-use-incomplete-tile flag when it is
known, rather than resetting it to false in one place and
hoping it will always be set again correctly in all cases.

The test times-out without this patch.

BUG=284810

Review URL: https://chromiumcodereview.appspot.com/23686011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221891 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 9 insertions, 10 deletions

diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 5fd5a99..d3e7aa5 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -65,8 +65,8 @@ void Scheduler::SetNeedsRedraw() {
   ProcessScheduledActions();
 }
 
-void Scheduler::DidSwapUseIncompleteTile() {
-  state_machine_.DidSwapUseIncompleteTile();
+void Scheduler::SetSwapUsedIncompleteTile(bool used_incomplete_tile) {
+  state_machine_.SetSwapUsedIncompleteTile(used_incomplete_tile);
   ProcessScheduledActions();
 }
 
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index c573af7..063872b 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -77,7 +77,7 @@ class CC_EXPORT Scheduler {
 
   void SetMainThreadNeedsLayerTextures();
 
-  void DidSwapUseIncompleteTile();
+  void SetSwapUsedIncompleteTile(bool used_incomplete_tile);
 
   void FinishCommit();
   void BeginFrameAbortedByMainThread(bool did_handle);
diff --git a/cc/scheduler/scheduler_state_machine.cc b/cc/scheduler/scheduler_state_machine.cc
index e93d0c8..a608fb9 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -673,10 +673,8 @@ void SchedulerStateMachine::UpdateStateOnDraw(bool did_swap) {
   draw_if_possible_failed_ = false;
   active_tree_needs_first_draw_ = false;
 
-  if (did_swap) {
-    swap_used_incomplete_tile_ = false;
+  if (did_swap)
     last_frame_number_swap_performed_ = current_frame_number_;
-  }
 }
 
 void SchedulerStateMachine::SetMainThreadNeedsLayerTextures() {
@@ -759,8 +757,9 @@ void SchedulerStateMachine::SetVisible(bool visible) { visible_ = visible; }
 
 void SchedulerStateMachine::SetNeedsRedraw() { needs_redraw_ = true; }
 
-void SchedulerStateMachine::DidSwapUseIncompleteTile() {
-  swap_used_incomplete_tile_ = true;
+void SchedulerStateMachine::SetSwapUsedIncompleteTile(
+    bool used_incomplete_tile) {
+  swap_used_incomplete_tile_ = used_incomplete_tile;
 }
 
 void SchedulerStateMachine::DidDrawIfPossibleCompleted(bool success) {
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index d69f70d..aaefa37 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -128,9 +128,9 @@ class CC_EXPORT SchedulerStateMachine {
   // or the screen being damaged and simply needing redisplay.
   void SetNeedsRedraw();
 
-  // Indicates that a redraw is required because we are currently rendering
+  // Indicates whether a redraw is required because we are currently rendering
   // with a low resolution or checkerboarded tile.
-  void DidSwapUseIncompleteTile();
+  void SetSwapUsedIncompleteTile(bool used_incomplete_tile);
 
   // Indicates whether ACTION_DRAW_AND_SWAP_IF_POSSIBLE drew to the screen or
   // not.