cc: Limit ManageTiles calls to once per-frame on average

cc/scheduler/scheduler_unittest.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.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 1076 matching lines @@
   scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
   EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
   client.Reset();
   scheduler->OnBeginImplFrameDeadline();
   EXPECT_EQ(0, client.num_draws());
   EXPECT_FALSE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
   EXPECT_TRUE(client.HasAction("ScheduledActionManageTiles"));
 }
 
 // Test that ManageTiles only happens once per frame.  If an external caller
-// initiates it, then the state machine should not on that frame.
+// initiates it, then the state machine should not ManageTiles on that frame.
 TEST(SchedulerTest, ManageTilesOncePerFrame) {
   FakeSchedulerClient client;
   SchedulerSettings default_scheduler_settings;
   Scheduler* scheduler = client.CreateScheduler(default_scheduler_settings);
   scheduler->SetCanStart();
   scheduler->SetVisible(true);
   scheduler->SetCanDraw(true);
   InitializeOutputSurfaceAndFirstCommit(scheduler);
 
   // If DidManageTiles during a frame, then ManageTiles should not occur again.
   scheduler->SetNeedsManageTiles();
   scheduler->SetNeedsRedraw();
   client.Reset();
   scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
   EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
 
   EXPECT_TRUE(scheduler->ManageTilesPending());
-  scheduler->DidManageTiles();
+  scheduler->DidManageTiles();  // An explicit ManageTiles.
   EXPECT_FALSE(scheduler->ManageTilesPending());
 
   client.Reset();
   scheduler->OnBeginImplFrameDeadline();
   EXPECT_EQ(1, client.num_draws());
   EXPECT_TRUE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
   EXPECT_FALSE(client.HasAction("ScheduledActionManageTiles"));
   EXPECT_FALSE(scheduler->RedrawPending());
   EXPECT_FALSE(scheduler->ManageTilesPending());
 
   // Next frame without DidManageTiles should ManageTiles with draw.
   scheduler->SetNeedsManageTiles();
   scheduler->SetNeedsRedraw();
   client.Reset();
   scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
   EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
 
   client.Reset();
   scheduler->OnBeginImplFrameDeadline();
   EXPECT_EQ(1, client.num_draws());
   EXPECT_TRUE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
   EXPECT_TRUE(client.HasAction("ScheduledActionManageTiles"));
   EXPECT_LT(client.ActionIndex("ScheduledActionDrawAndSwapIfPossible"),
             client.ActionIndex("ScheduledActionManageTiles"));
   EXPECT_FALSE(scheduler->RedrawPending());
   EXPECT_FALSE(scheduler->ManageTilesPending());
+  scheduler->DidManageTiles();  // Corresponds to ScheduledActionManageTiles
+
+  // If we get another DidManageTiles within the same frame, we should
+  // not ManageTiles on the next frame.
+  scheduler->DidManageTiles();  // An explicit ManageTiles.
+  scheduler->SetNeedsManageTiles();
+  scheduler->SetNeedsRedraw();
+  client.Reset();
+  scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
+
+  EXPECT_TRUE(scheduler->ManageTilesPending());
+
+  client.Reset();
+  scheduler->OnBeginImplFrameDeadline();
+  EXPECT_EQ(1, client.num_draws());
+  EXPECT_TRUE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
+  EXPECT_FALSE(client.HasAction("ScheduledActionManageTiles"));
+  EXPECT_FALSE(scheduler->RedrawPending());
+
+  // If we get another DidManageTiles, we should not ManageTiles on the next
+  // frame. This verifies we don't alternate calling ManageTiles once and twice.
+  EXPECT_TRUE(scheduler->ManageTilesPending());
+  scheduler->DidManageTiles();  // An explicit ManageTiles.
+  EXPECT_FALSE(scheduler->ManageTilesPending());
+  scheduler->SetNeedsManageTiles();
+  scheduler->SetNeedsRedraw();
+  client.Reset();
+  scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
+
+  EXPECT_TRUE(scheduler->ManageTilesPending());
+
+  client.Reset();
+  scheduler->OnBeginImplFrameDeadline();
+  EXPECT_EQ(1, client.num_draws());
+  EXPECT_TRUE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
+  EXPECT_FALSE(client.HasAction("ScheduledActionManageTiles"));
+  EXPECT_FALSE(scheduler->RedrawPending());
+
+  // Next frame without DidManageTiles should ManageTiles with draw.
+  scheduler->SetNeedsManageTiles();
+  scheduler->SetNeedsRedraw();
+  client.Reset();
+  scheduler->BeginImplFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_SINGLE_ACTION("PostBeginImplFrameDeadlineTask", client);
+
+  client.Reset();
+  scheduler->OnBeginImplFrameDeadline();
+  EXPECT_EQ(1, client.num_draws());
+  EXPECT_TRUE(client.HasAction("ScheduledActionDrawAndSwapIfPossible"));
+  EXPECT_TRUE(client.HasAction("ScheduledActionManageTiles"));
+  EXPECT_LT(client.ActionIndex("ScheduledActionDrawAndSwapIfPossible"),
+            client.ActionIndex("ScheduledActionManageTiles"));
+  EXPECT_FALSE(scheduler->RedrawPending());
+  EXPECT_FALSE(scheduler->ManageTilesPending());
+  scheduler->DidManageTiles();  // Corresponds to ScheduledActionManageTiles
 }
 
 class SchedulerClientWithFixedEstimates : public FakeSchedulerClient {
  public:
   SchedulerClientWithFixedEstimates(
       base::TimeDelta draw_duration,
       base::TimeDelta begin_main_frame_to_commit_duration,
       base::TimeDelta commit_to_activate_duration)
       : draw_duration_(draw_duration),
         begin_main_frame_to_commit_duration_(
@@ skipping 125 matching lines @@
     SpinForMillis(interval * 2);
     EXPECT_GT(client.num_actions_(), actions_so_far);
     EXPECT_STREQ(client.Action(client.num_actions_() - 1),
                  "DidAnticipatedDrawTimeChange");
     actions_so_far = client.num_actions_();
   }
 }
 
 }  // namespace
 }  // namespace cc