Make SingleThreadProxy a SchedulerClient

This makes ui::Compositor no longer in charge of
scheduling commits and draws, deferring it to cc::Scheduler.

BUG=329552, 287250

Review URL: https://codereview.chromium.org/134623005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@280493 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 388 insertions, 211 deletions

diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 4a682cd..8f127e9 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -77,11 +77,11 @@ Scheduler::Scheduler(
     SchedulerClient* client,
     const SchedulerSettings& scheduler_settings,
     int layer_tree_host_id,
-    const scoped_refptr<base::SingleThreadTaskRunner>& impl_task_runner)
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
     : settings_(scheduler_settings),
       client_(client),
       layer_tree_host_id_(layer_tree_host_id),
-      impl_task_runner_(impl_task_runner),
+      task_runner_(task_runner),
       vsync_interval_(BeginFrameArgs::DefaultInterval()),
       last_set_needs_begin_frame_(false),
       begin_unthrottled_frame_posted_(false),
@@ -126,7 +126,7 @@ Scheduler::~Scheduler() {
 void Scheduler::SetupSyntheticBeginFrames() {
   DCHECK(!synthetic_begin_frame_source_);
   synthetic_begin_frame_source_.reset(
-      new SyntheticBeginFrameSource(this, impl_task_runner_.get()));
+      new SyntheticBeginFrameSource(this, task_runner_.get()));
 }
 
 void Scheduler::CommitVSyncParameters(base::TimeTicks timebase,
@@ -272,6 +272,9 @@ base::TimeTicks Scheduler::LastBeginImplFrameTime() {
 }
 
 void Scheduler::SetupNextBeginFrameIfNeeded() {
+  if (!task_runner_)
+    return;
+
   bool needs_begin_frame = state_machine_.BeginFrameNeeded();
 
   if (settings_.throttle_frame_production) {
@@ -326,7 +329,7 @@ void Scheduler::SetupNextBeginFrameWhenVSyncThrottlingDisabled(
   }
 
   begin_unthrottled_frame_posted_ = true;
-  impl_task_runner_->PostTask(FROM_HERE, begin_unthrottled_frame_closure_);
+  task_runner_->PostTask(FROM_HERE, begin_unthrottled_frame_closure_);
 }
 
 // BeginUnthrottledFrame is used when we aren't throttling frame production.
@@ -360,7 +363,7 @@ void Scheduler::SetupPollingMechanisms(bool needs_begin_frame) {
       base::TimeDelta delay = begin_impl_frame_args_.IsValid()
                                   ? begin_impl_frame_args_.interval
                                   : BeginFrameArgs::DefaultInterval();
-      impl_task_runner_->PostDelayedTask(
+      task_runner_->PostDelayedTask(
           FROM_HERE, poll_for_draw_triggers_task_.callback(), delay);
     }
   } else {
@@ -385,9 +388,9 @@ void Scheduler::SetupPollingMechanisms(bool needs_begin_frame) {
       // Since we'd rather get a BeginImplFrame by the normal mechanism, we
       // set the interval to twice the interval from the previous frame.
       advance_commit_state_task_.Reset(advance_commit_state_closure_);
-      impl_task_runner_->PostDelayedTask(FROM_HERE,
-                                         advance_commit_state_task_.callback(),
-                                         begin_impl_frame_args_.interval * 2);
+      task_runner_->PostDelayedTask(FROM_HERE,
+                                    advance_commit_state_task_.callback(),
+                                    begin_impl_frame_args_.interval * 2);
     }
   } else {
     advance_commit_state_task_.Cancel();
@@ -489,7 +492,7 @@ void Scheduler::PostBeginRetroFrameIfNeeded() {
     return;
 
   begin_retro_frame_posted_ = true;
-  impl_task_runner_->PostTask(FROM_HERE, begin_retro_frame_closure_);
+  task_runner_->PostTask(FROM_HERE, begin_retro_frame_closure_);
 }
 
 // BeginImplFrame starts a compositor frame that will wait up until a deadline
@@ -497,8 +500,8 @@ void Scheduler::PostBeginRetroFrameIfNeeded() {
 // any asynchronous animation and scroll/pinch updates.
 void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   TRACE_EVENT1("cc", "Scheduler::BeginImplFrame", "args", ToTrace(args));
-  DCHECK(state_machine_.begin_impl_frame_state() ==
-         SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+  DCHECK_EQ(state_machine_.begin_impl_frame_state(),
+            SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
   DCHECK(state_machine_.HasInitializedOutputSurface());
 
   advance_commit_state_task_.Cancel();
@@ -565,7 +568,7 @@ void Scheduler::ScheduleBeginImplFrameDeadline(base::TimeTicks deadline) {
   base::TimeDelta delta = deadline - gfx::FrameTime::Now();
   if (delta <= base::TimeDelta())
     delta = base::TimeDelta();
-  impl_task_runner_->PostDelayedTask(
+  task_runner_->PostDelayedTask(
       FROM_HERE, begin_impl_frame_deadline_task_.callback(), delta);
 }
 
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 3de06ac..f392047 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -54,9 +54,9 @@ class CC_EXPORT Scheduler {
       SchedulerClient* client,
       const SchedulerSettings& scheduler_settings,
       int layer_tree_host_id,
-      const scoped_refptr<base::SingleThreadTaskRunner>& impl_task_runner) {
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
     return make_scoped_ptr(new Scheduler(
-        client, scheduler_settings, layer_tree_host_id, impl_task_runner));
+        client, scheduler_settings, layer_tree_host_id, task_runner));
   }
 
   virtual ~Scheduler();
@@ -170,16 +170,15 @@ class CC_EXPORT Scheduler {
     scoped_refptr<DelayBasedTimeSource> time_source_;
   };
 
-  Scheduler(
-      SchedulerClient* client,
-      const SchedulerSettings& scheduler_settings,
-      int layer_tree_host_id,
-      const scoped_refptr<base::SingleThreadTaskRunner>& impl_task_runner);
+  Scheduler(SchedulerClient* client,
+            const SchedulerSettings& scheduler_settings,
+            int layer_tree_host_id,
+            const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
 
   const SchedulerSettings settings_;
   SchedulerClient* client_;
   int layer_tree_host_id_;
-  scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   base::TimeDelta vsync_interval_;
   base::TimeDelta estimated_parent_draw_time_;
diff --git a/cc/scheduler/scheduler_state_machine.cc b/cc/scheduler/scheduler_state_machine.cc
index dea25b40..e2e8168 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -1006,7 +1006,9 @@ void SchedulerStateMachine::DidDrawIfPossibleCompleted(DrawResult result) {
   }
 }
 
-void SchedulerStateMachine::SetNeedsCommit() { needs_commit_ = true; }
+void SchedulerStateMachine::SetNeedsCommit() {
+  needs_commit_ = true;
+}
 
 void SchedulerStateMachine::NotifyReadyToCommit() {
   DCHECK(commit_state_ == COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED) << *AsValue();
diff --git a/cc/test/fake_layer_tree_host_client.h b/cc/test/fake_layer_tree_host_client.h
index f928453..7f7bd35 100644
--- a/cc/test/fake_layer_tree_host_client.h
+++ b/cc/test/fake_layer_tree_host_client.h
@@ -42,8 +42,6 @@ class FakeLayerTreeHostClient : public LayerTreeHostClient,
   virtual void DidCompleteSwapBuffers() OVERRIDE {}
 
   // LayerTreeHostSingleThreadClient implementation.
-  virtual void ScheduleComposite() OVERRIDE {}
-  virtual void ScheduleAnimation() OVERRIDE {}
   virtual void DidPostSwapBuffers() OVERRIDE {}
   virtual void DidAbortSwapBuffers() OVERRIDE {}
 
diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index 3437f8c..a680441 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -321,14 +321,6 @@ class LayerTreeHostClientForTesting : public LayerTreeHostClient,
     test_hooks_->DidCompleteSwapBuffers();
   }
 
-  virtual void ScheduleComposite() OVERRIDE {
-    test_hooks_->ScheduleComposite();
-  }
-
-  virtual void ScheduleAnimation() OVERRIDE {
-    test_hooks_->ScheduleAnimation();
-  }
-
   virtual void DidPostSwapBuffers() OVERRIDE {}
   virtual void DidAbortSwapBuffers() OVERRIDE {}
 
@@ -401,7 +393,6 @@ LayerTreeTest::LayerTreeTest()
       end_when_begin_returns_(false),
       timed_out_(false),
       scheduled_(false),
-      schedule_when_set_visible_true_(false),
       started_(false),
       ended_(false),
       delegating_renderer_(false),
@@ -564,15 +555,6 @@ void LayerTreeTest::Timeout() {
   EndTest();
 }
 
-void LayerTreeTest::ScheduleComposite() {
-  if (!started_ || scheduled_)
-    return;
-  scheduled_ = true;
-  main_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&LayerTreeTest::DispatchComposite, main_thread_weak_ptr_));
-}
-
 void LayerTreeTest::RealEndTest() {
   if (layer_tree_host_ && proxy()->CommitPendingForTesting()) {
     main_task_runner_->PostTask(
@@ -624,16 +606,8 @@ void LayerTreeTest::DispatchSetNeedsRedrawRect(const gfx::Rect& damage_rect) {
 
 void LayerTreeTest::DispatchSetVisible(bool visible) {
   DCHECK(!proxy() || proxy()->IsMainThread());
-
-  if (!layer_tree_host_)
-    return;
-
-  layer_tree_host_->SetVisible(visible);
-
-  // If the LTH is being made visible and a previous ScheduleComposite() was
-  // deferred because the LTH was not visible, re-schedule the composite now.
-  if (layer_tree_host_->visible() && schedule_when_set_visible_true_)
-    ScheduleComposite();
+  if (layer_tree_host_)
+    layer_tree_host_->SetVisible(visible);
 }
 
 void LayerTreeTest::DispatchSetNextCommitForcesRedraw() {
@@ -643,24 +617,6 @@ void LayerTreeTest::DispatchSetNextCommitForcesRedraw() {
     layer_tree_host_->SetNextCommitForcesRedraw();
 }
 
-void LayerTreeTest::DispatchComposite() {
-  scheduled_ = false;
-
-  if (!layer_tree_host_)
-    return;
-
-  // If the LTH is not visible, defer the composite until the LTH is made
-  // visible.
-  if (!layer_tree_host_->visible()) {
-    schedule_when_set_visible_true_ = true;
-    return;
-  }
-
-  schedule_when_set_visible_true_ = false;
-  base::TimeTicks now = gfx::FrameTime::Now();
-  layer_tree_host_->Composite(now);
-}
-
 void LayerTreeTest::RunTest(bool threaded,
                             bool delegating_renderer,
                             bool impl_side_painting) {
diff --git a/cc/test/layer_tree_test.h b/cc/test/layer_tree_test.h
index 8f38dda..619ae96 100644
--- a/cc/test/layer_tree_test.h
+++ b/cc/test/layer_tree_test.h
@@ -71,8 +71,6 @@ class TestHooks : public AnimationDelegate {
   virtual void DidCommit() {}
   virtual void DidCommitAndDrawFrame() {}
   virtual void DidCompleteSwapBuffers() {}
-  virtual void ScheduleComposite() {}
-  virtual void ScheduleAnimation() {}
   virtual void DidDeferCommit() {}
   virtual void DidSetVisibleOnImplTree(LayerTreeHostImpl* host_impl,
                                        bool visible) {}
@@ -139,8 +137,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
 
   virtual void InitializeSettings(LayerTreeSettings* settings) {}
 
-  virtual void ScheduleComposite() OVERRIDE;
-
   void RealEndTest();
 
   virtual void DispatchAddAnimation(Layer* layer_to_receive_animation,
@@ -151,7 +147,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
   void DispatchSetNeedsRedrawRect(const gfx::Rect& damage_rect);
   void DispatchSetVisible(bool visible);
   void DispatchSetNextCommitForcesRedraw();
-  void DispatchComposite();
   void DispatchDidAddAnimation();
 
   virtual void AfterTest() = 0;
@@ -204,7 +199,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
   bool end_when_begin_returns_;
   bool timed_out_;
   bool scheduled_;
-  bool schedule_when_set_visible_true_;
   bool started_;
   bool ended_;
   bool delegating_renderer_;
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 51b9b4f..6f995d8 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -677,6 +677,8 @@ void LayerTreeHost::Composite(base::TimeTicks frame_begin_time) {
   DCHECK(!proxy_->HasImplThread());
   SingleThreadProxy* proxy = static_cast<SingleThreadProxy*>(proxy_.get());
 
+  SetLayerTreeHostClientReady();
+
   if (output_surface_lost_)
     proxy->CreateAndInitializeOutputSurface();
   if (output_surface_lost_)
diff --git a/cc/trees/layer_tree_host_single_thread_client.h b/cc/trees/layer_tree_host_single_thread_client.h
index cb61450..dbca28c 100644
--- a/cc/trees/layer_tree_host_single_thread_client.h
+++ b/cc/trees/layer_tree_host_single_thread_client.h
@@ -10,10 +10,10 @@ namespace cc {
 class LayerTreeHostSingleThreadClient {
  public:
   // Request that the client schedule a composite.
-  virtual void ScheduleComposite() = 0;
+  virtual void ScheduleComposite() {}
   // Request that the client schedule a composite now, and calculate appropriate
   // delay for potential future frame.
-  virtual void ScheduleAnimation() = 0;
+  virtual void ScheduleAnimation() {}
 
   // Called whenever the compositor posts a SwapBuffers (either full or
   // partial). After DidPostSwapBuffers(), exactly one of
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index b194491..95c44bcf 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -91,8 +91,8 @@ class LayerTreeHostTestSetNeedsCommit1 : public LayerTreeHostTest {
   }
 
   virtual void AfterTest() OVERRIDE {
-    EXPECT_GE(1, num_commits_);
-    EXPECT_GE(1, num_draws_);
+    EXPECT_LE(1, num_commits_);
+    EXPECT_LE(1, num_draws_);
   }
 
  private:
@@ -1967,7 +1967,7 @@ class LayerTreeHostTestDeferCommits : public LayerTreeHostTest {
   int num_complete_commits_;
 };
 
-MULTI_THREAD_TEST_F(LayerTreeHostTestDeferCommits);
+SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestDeferCommits);
 
 class LayerTreeHostWithProxy : public LayerTreeHost {
  public:
diff --git a/cc/trees/layer_tree_host_unittest_animation.cc b/cc/trees/layer_tree_host_unittest_animation.cc
index 1542a14..3b2de64 100644
--- a/cc/trees/layer_tree_host_unittest_animation.cc
+++ b/cc/trees/layer_tree_host_unittest_animation.cc
@@ -726,9 +726,7 @@ class LayerTreeHostAnimationTestContinuousAnimate
     : public LayerTreeHostAnimationTest {
  public:
   LayerTreeHostAnimationTestContinuousAnimate()
-      : num_commit_complete_(0),
-        num_draw_layers_(0) {
-  }
+      : num_commit_complete_(0), num_draw_layers_(0), have_animated_(false) {}
 
   virtual void SetupTree() OVERRIDE {
     LayerTreeHostAnimationTest::SetupTree();
@@ -747,6 +745,7 @@ class LayerTreeHostAnimationTestContinuousAnimate
     if (num_draw_layers_ == 2)
       return;
     layer_tree_host()->SetNeedsAnimate();
+    have_animated_ = true;
   }
 
   virtual void Layout() OVERRIDE {
@@ -767,16 +766,18 @@ class LayerTreeHostAnimationTestContinuousAnimate
   virtual void AfterTest() OVERRIDE {
     // Check that we didn't commit twice between first and second draw.
     EXPECT_EQ(1, num_commit_complete_);
+    EXPECT_TRUE(have_animated_);
   }
 
  private:
   int num_commit_complete_;
   int num_draw_layers_;
+  bool have_animated_;
   FakeContentLayerClient client_;
   scoped_refptr<FakeContentLayer> content_;
 };
 
-MULTI_THREAD_TEST_F(LayerTreeHostAnimationTestContinuousAnimate);
+SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostAnimationTestContinuousAnimate);
 
 class LayerTreeHostAnimationTestCancelAnimateCommit
     : public LayerTreeHostAnimationTest {
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index 879e534..548ff36 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -65,6 +65,9 @@ class LayerTreeHostContextTest : public LayerTreeTest {
   }
 
   void LoseContext() {
+    // For sanity-checking tests, they should only call this when the
+    // context is not lost.
+    CHECK(context3d_);
     context3d_->loseContextCHROMIUM(GL_GUILTY_CONTEXT_RESET_ARB,
                                     GL_INNOCENT_CONTEXT_RESET_ARB);
     context3d_ = NULL;
@@ -200,45 +203,53 @@ class LayerTreeHostContextTestLostContextSucceeds
     static const TestCase kTests[] = {
         // Losing the context and failing to recreate it (or losing it again
         // immediately) a small number of times should succeed.
-        {1,      // times_to_lose_during_commit
+        {
+         1,      // times_to_lose_during_commit
          0,      // times_to_lose_during_draw
          0,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
-        {0,      // times_to_lose_during_commit
+        {
+         0,      // times_to_lose_during_commit
          1,      // times_to_lose_during_draw
          0,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
-        {1,      // times_to_lose_during_commit
+        {
+         1,      // times_to_lose_during_commit
          0,      // times_to_lose_during_draw
          3,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
-        {0,      // times_to_lose_during_commit
+        {
+         0,      // times_to_lose_during_commit
          1,      // times_to_lose_during_draw
          3,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
         // Losing the context and recreating it any number of times should
         // succeed.
-        {10,     // times_to_lose_during_commit
+        {
+         10,     // times_to_lose_during_commit
          0,      // times_to_lose_during_draw
          0,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
-        {0,      // times_to_lose_during_commit
+        {
+         0,      // times_to_lose_during_commit
          10,     // times_to_lose_during_draw
          0,      // times_to_fail_recreate
          false,  // fallback_context_works
         },
         // Losing the context, failing to reinitialize it, and making a fallback
         // context should work.
-        {0,     // times_to_lose_during_commit
+        {
+         0,     // times_to_lose_during_commit
          1,     // times_to_lose_during_draw
          0,     // times_to_fail_recreate
          true,  // fallback_context_works
-        }, };
+        },
+    };
 
     if (test_case_ >= arraysize(kTests))
       return false;
@@ -300,7 +311,8 @@ class LayerTreeHostClientNotReadyDoesNotCreateOutputSurface
   }
 };
 
-MULTI_THREAD_TEST_F(LayerTreeHostClientNotReadyDoesNotCreateOutputSurface);
+SINGLE_AND_MULTI_THREAD_TEST_F(
+    LayerTreeHostClientNotReadyDoesNotCreateOutputSurface);
 
 class LayerTreeHostContextTestLostContextSucceedsWithContent
     : public LayerTreeHostContextTestLostContextSucceeds {
@@ -358,10 +370,11 @@ class LayerTreeHostContextTestCreateOutputSurfaceFails
       : times_to_fail_(times_to_fail),
         expect_fallback_attempt_(expect_fallback_attempt),
         did_attempt_fallback_(false),
-        times_initialized_(0) {}
+        times_initialized_(0) {
+    times_to_fail_create_ = times_to_fail_;
+  }
 
   virtual void BeginTest() OVERRIDE {
-    times_to_fail_create_ = times_to_fail_;
     PostSetNeedsCommitToMainThread();
   }
 
@@ -975,12 +988,6 @@ class ScrollbarLayerLostContext : public LayerTreeHostContextTest {
         EXPECT_EQ(2, scrollbar_layer_->update_count());
         EndTest();
         break;
-      case 3:
-        // Single thread proxy issues extra commits after context lost.
-        // http://crbug.com/287250
-        if (HasImplThread())
-          NOTREACHED();
-        break;
       default:
         NOTREACHED();
     }
@@ -1024,12 +1031,10 @@ class UIResourceLostTest : public LayerTreeHostContextTest {
 
   void PostLoseContextToImplThread() {
     EXPECT_TRUE(layer_tree_host()->proxy()->IsMainThread());
-    base::SingleThreadTaskRunner* task_runner =
-        HasImplThread() ? ImplThreadTaskRunner()
-                        : base::MessageLoopProxy::current();
-    task_runner->PostTask(FROM_HERE,
-                          base::Bind(&LayerTreeHostContextTest::LoseContext,
-                                     base::Unretained(this)));
+    ImplThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&LayerTreeHostContextTest::LoseContext,
+                   base::Unretained(this)));
   }
 
  protected:
@@ -1084,13 +1089,8 @@ class UIResourceLostAfterCommit : public UIResourceLostTestSimple {
         EndTest();
         break;
       case 5:
-        // Single thread proxy issues extra commits after context lost.
-        // http://crbug.com/287250
-        if (HasImplThread())
-          NOTREACHED();
-        break;
-      case 6:
         NOTREACHED();
+        break;
     }
   }
 
@@ -1178,13 +1178,8 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         EndTest();
         break;
       case 6:
-        // Single thread proxy issues extra commits after context lost.
-        // http://crbug.com/287250
-        if (HasImplThread())
-          NOTREACHED();
-        break;
-      case 8:
         NOTREACHED();
+        break;
     }
   }
 
@@ -1205,15 +1200,8 @@ class UIResourceLostBeforeCommit : public UIResourceLostTestSimple {
         // Sequence 2 (continued):
         // The previous resource should have been deleted.
         EXPECT_EQ(0u, impl->ResourceIdForUIResource(test_id0_));
-        if (HasImplThread()) {
-          // The second resource should have been created.
-          EXPECT_NE(0u, impl->ResourceIdForUIResource(test_id1_));
-        } else {
-          // The extra commit that happens at context lost in the single thread
-          // proxy changes the timing so that the resource has been destroyed.
-          // http://crbug.com/287250
-          EXPECT_EQ(0u, impl->ResourceIdForUIResource(test_id1_));
-        }
+        // The second resource should have been created.
+        EXPECT_NE(0u, impl->ResourceIdForUIResource(test_id1_));
         // The second resource called the resource callback once and since the
         // context is lost, a "resource lost" callback was also issued.
         EXPECT_EQ(2, ui_resource_->resource_create_count);
@@ -1529,8 +1517,8 @@ class LayerTreeHostContextTestLoseAfterSendingBeginMainFrame
   bool deferred_;
 };
 
-// TODO(danakj): We don't use scheduler with SingleThreadProxy yet.
-MULTI_THREAD_TEST_F(LayerTreeHostContextTestLoseAfterSendingBeginMainFrame);
+SINGLE_AND_MULTI_THREAD_TEST_F(
+    LayerTreeHostContextTestLoseAfterSendingBeginMainFrame);
 
 }  // namespace
 }  // namespace cc
diff --git a/cc/trees/layer_tree_host_unittest_no_message_loop.cc b/cc/trees/layer_tree_host_unittest_no_message_loop.cc
index 4c6796f..f687efb 100644
--- a/cc/trees/layer_tree_host_unittest_no_message_loop.cc
+++ b/cc/trees/layer_tree_host_unittest_no_message_loop.cc
@@ -74,8 +74,6 @@ class LayerTreeHostNoMessageLoopTest
   virtual void DidCompleteSwapBuffers() OVERRIDE {}
 
   // LayerTreeHostSingleThreadClient overrides.
-  virtual void ScheduleComposite() OVERRIDE {}
-  virtual void ScheduleAnimation() OVERRIDE {}
   virtual void DidPostSwapBuffers() OVERRIDE {}
   virtual void DidAbortSwapBuffers() OVERRIDE {}
 
diff --git a/cc/trees/layer_tree_settings.cc b/cc/trees/layer_tree_settings.cc
index 4b56d7c..5193b2d 100644
--- a/cc/trees/layer_tree_settings.cc
+++ b/cc/trees/layer_tree_settings.cc
@@ -16,6 +16,7 @@ LayerTreeSettings::LayerTreeSettings()
     : impl_side_painting(false),
       allow_antialiasing(true),
       throttle_frame_production(true),
+      single_thread_proxy_scheduler(true),
       begin_frame_scheduling_enabled(false),
       main_frame_before_draw_enabled(true),
       main_frame_before_activation_enabled(false),
diff --git a/cc/trees/layer_tree_settings.h b/cc/trees/layer_tree_settings.h
index 21d72c9..ef2a4955 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -21,6 +21,7 @@ class CC_EXPORT LayerTreeSettings {
   bool impl_side_painting;
   bool allow_antialiasing;
   bool throttle_frame_production;
+  bool single_thread_proxy_scheduler;
   bool begin_frame_scheduling_enabled;
   bool main_frame_before_draw_enabled;
   bool main_frame_before_activation_enabled;
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index c254311..46d0814 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -33,7 +33,11 @@ SingleThreadProxy::SingleThreadProxy(LayerTreeHost* layer_tree_host,
       layer_tree_host_(layer_tree_host),
       client_(client),
       next_frame_is_newly_committed_frame_(false),
-      inside_draw_(false) {
+      inside_draw_(false),
+      defer_commits_(false),
+      commit_was_deferred_(false),
+      commit_requested_(false),
+      weak_factory_(this) {
   TRACE_EVENT0("cc", "SingleThreadProxy::SingleThreadProxy");
   DCHECK(Proxy::IsMainThread());
   DCHECK(layer_tree_host);
@@ -73,13 +77,26 @@ void SingleThreadProxy::SetLayerTreeHostClientReady() {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetLayerTreeHostClientReady");
   // Scheduling is controlled by the embedder in the single thread case, so
   // nothing to do.
+  DCHECK(Proxy::IsMainThread());
+  DebugScopedSetImplThread impl(this);
+  if (layer_tree_host_->settings().single_thread_proxy_scheduler &&
+      !scheduler_on_impl_thread_) {
+    SchedulerSettings scheduler_settings(layer_tree_host_->settings());
+    scheduler_on_impl_thread_ = Scheduler::Create(this,
+                                                  scheduler_settings,
+                                                  layer_tree_host_->id(),
+                                                  MainThreadTaskRunner());
+    scheduler_on_impl_thread_->SetCanStart();
+    scheduler_on_impl_thread_->SetVisible(layer_tree_host_impl_->visible());
+  }
 }
 
 void SingleThreadProxy::SetVisible(bool visible) {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetVisible");
   DebugScopedSetImplThread impl(this);
   layer_tree_host_impl_->SetVisible(visible);
-
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->SetVisible(layer_tree_host_impl_->visible());
   // Changing visibility could change ShouldComposite().
   UpdateBackgroundAnimateTicking();
 }
@@ -106,9 +123,14 @@ void SingleThreadProxy::CreateAndInitializeOutputSurface() {
 
   layer_tree_host_->OnCreateAndInitializeOutputSurfaceAttempted(success);
 
-  if (!success) {
-    // Force another recreation attempt to happen by requesting another commit.
-    SetNeedsCommit();
+  if (success) {
+    if (scheduler_on_impl_thread_)
+      scheduler_on_impl_thread_->DidCreateAndInitializeOutputSurface();
+  } else if (Proxy::MainThreadTaskRunner()) {
+    Proxy::MainThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&SingleThreadProxy::CreateAndInitializeOutputSurface,
+                   weak_factory_.GetWeakPtr()));
   }
 }
 
@@ -122,17 +144,40 @@ void SingleThreadProxy::SetNeedsAnimate() {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsAnimate");
   DCHECK(Proxy::IsMainThread());
   client_->ScheduleAnimation();
+  SetNeedsCommit();
 }
 
 void SingleThreadProxy::SetNeedsUpdateLayers() {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsUpdateLayers");
   DCHECK(Proxy::IsMainThread());
-  client_->ScheduleComposite();
+  SetNeedsCommit();
 }
 
-void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
+void SingleThreadProxy::DoCommit(base::TimeTicks frame_begin_time) {
   TRACE_EVENT0("cc", "SingleThreadProxy::DoCommit");
   DCHECK(Proxy::IsMainThread());
+  layer_tree_host_->WillBeginMainFrame();
+  layer_tree_host_->Layout();
+  layer_tree_host_->UpdateClientAnimations(frame_begin_time);
+  layer_tree_host_->AnimateLayers(frame_begin_time);
+  commit_requested_ = false;
+
+  if (PrioritizedResourceManager* contents_texture_manager =
+          layer_tree_host_->contents_texture_manager()) {
+    contents_texture_manager->UnlinkAndClearEvictedBackings();
+    contents_texture_manager->SetMaxMemoryLimitBytes(
+        layer_tree_host_impl_->memory_allocation_limit_bytes());
+    contents_texture_manager->SetExternalPriorityCutoff(
+        layer_tree_host_impl_->memory_allocation_priority_cutoff());
+  }
+
+  scoped_ptr<ResourceUpdateQueue> queue =
+      make_scoped_ptr(new ResourceUpdateQueue);
+
+  layer_tree_host_->UpdateLayers(queue.get());
+
+  layer_tree_host_->WillCommit();
+
   // Commit immediately.
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
@@ -166,6 +211,8 @@ void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
 
     layer_tree_host_impl_->CommitComplete();
 
+    UpdateBackgroundAnimateTicking();
+
 #if DCHECK_IS_ON
     // In the single-threaded case, the scale and scroll deltas should never be
     // touched on the impl layer tree.
@@ -182,32 +229,64 @@ void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
     stats_instrumentation->AccumulateAndClearMainThreadStats();
   }
   layer_tree_host_->CommitComplete();
+  layer_tree_host_->DidBeginMainFrame();
+  timing_history_.DidCommit();
+
   next_frame_is_newly_committed_frame_ = true;
 }
 
 void SingleThreadProxy::SetNeedsCommit() {
   DCHECK(Proxy::IsMainThread());
+  DebugScopedSetImplThread impl(this);
   client_->ScheduleComposite();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->SetNeedsCommit();
+  commit_requested_ = true;
 }
 
 void SingleThreadProxy::SetNeedsRedraw(const gfx::Rect& damage_rect) {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsRedraw");
-  SetNeedsRedrawRectOnImplThread(damage_rect);
+  DCHECK(Proxy::IsMainThread());
+  DebugScopedSetImplThread impl(this);
   client_->ScheduleComposite();
+  SetNeedsRedrawRectOnImplThread(damage_rect);
 }
 
 void SingleThreadProxy::SetNextCommitWaitsForActivation() {
   // There is no activation here other than commit. So do nothing.
+  DCHECK(Proxy::IsMainThread());
 }
 
 void SingleThreadProxy::SetDeferCommits(bool defer_commits) {
-  // Thread-only feature.
-  NOTREACHED();
+  DCHECK(Proxy::IsMainThread());
+  // Deferring commits only makes sense if there's a scheduler.
+  if (!scheduler_on_impl_thread_)
+    return;
+  if (defer_commits_ == defer_commits)
+    return;
+
+  if (defer_commits)
+    TRACE_EVENT_ASYNC_BEGIN0("cc", "SingleThreadProxy::SetDeferCommits", this);
+  else
+    TRACE_EVENT_ASYNC_END0("cc", "SingleThreadProxy::SetDeferCommits", this);
+
+  defer_commits_ = defer_commits;
+  if (!defer_commits_ && commit_was_deferred_) {
+    scheduler_on_impl_thread_->NotifyBeginMainFrameStarted();
+    scheduler_on_impl_thread_->NotifyReadyToCommit();
+    commit_was_deferred_ = false;
+  }
 }
 
-bool SingleThreadProxy::CommitRequested() const { return false; }
+bool SingleThreadProxy::CommitRequested() const {
+  DCHECK(Proxy::IsMainThread());
+  return commit_requested_;
+}
 
-bool SingleThreadProxy::BeginMainFrameRequested() const { return false; }
+bool SingleThreadProxy::BeginMainFrameRequested() const {
+  DCHECK(Proxy::IsMainThread());
+  return commit_requested_;
+}
 
 size_t SingleThreadProxy::MaxPartialTextureUpdates() const {
   return std::numeric_limits<size_t>::max();
@@ -223,6 +302,7 @@ void SingleThreadProxy::Stop() {
     BlockingTaskRunner::CapturePostTasks blocked;
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
+    scheduler_on_impl_thread_.reset();
     layer_tree_host_impl_.reset();
   }
   layer_tree_host_ = NULL;
@@ -233,15 +313,19 @@ void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
       "cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
   DCHECK(Proxy::IsImplThread());
   UpdateBackgroundAnimateTicking();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->SetCanDraw(can_draw);
 }
 
 void SingleThreadProxy::NotifyReadyToActivate() {
-  // Thread-only feature.
+  // Impl-side painting only.
   NOTREACHED();
 }
 
 void SingleThreadProxy::SetNeedsRedrawOnImplThread() {
   client_->ScheduleComposite();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->SetNeedsRedraw();
 }
 
 void SingleThreadProxy::SetNeedsAnimateOnImplThread() {
@@ -249,17 +333,14 @@ void SingleThreadProxy::SetNeedsAnimateOnImplThread() {
 }
 
 void SingleThreadProxy::SetNeedsManageTilesOnImplThread() {
-  // Thread-only/Impl-side-painting-only feature.
+  // Impl-side painting only.
   NOTREACHED();
 }
 
 void SingleThreadProxy::SetNeedsRedrawRectOnImplThread(
     const gfx::Rect& damage_rect) {
-  // TODO(brianderson): Once we move render_widget scheduling into this class,
-  // we can treat redraw requests more efficiently than CommitAndRedraw
-  // requests.
   layer_tree_host_impl_->SetViewportDamage(damage_rect);
-  SetNeedsCommit();
+  SetNeedsRedrawOnImplThread();
 }
 
 void SingleThreadProxy::DidInitializeVisibleTileOnImplThread() {
@@ -269,6 +350,8 @@ void SingleThreadProxy::DidInitializeVisibleTileOnImplThread() {
 
 void SingleThreadProxy::SetNeedsCommitOnImplThread() {
   client_->ScheduleComposite();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->SetNeedsCommit();
 }
 
 void SingleThreadProxy::PostAnimationEventsToMainThreadOnImplThread(
@@ -305,66 +388,58 @@ void SingleThreadProxy::UpdateRendererCapabilitiesOnImplThread() {
       layer_tree_host_impl_->GetRendererCapabilities().MainThreadCapabilities();
 }
 
+void SingleThreadProxy::DidActivatePendingTree() {
+  // Impl-side painting only.
+  NOTREACHED();
+}
+
+void SingleThreadProxy::DidManageTiles() {
+  // Impl-side painting only.
+  NOTREACHED();
+}
+
 void SingleThreadProxy::DidLoseOutputSurfaceOnImplThread() {
   TRACE_EVENT0("cc", "SingleThreadProxy::DidLoseOutputSurfaceOnImplThread");
-  // Cause a commit so we can notice the lost context.
-  SetNeedsCommitOnImplThread();
+  {
+    DebugScopedSetMainThread main(this);
+    // This must happen before we notify the scheduler as it may try to recreate
+    // the output surface if already in BEGIN_IMPL_FRAME_STATE_IDLE.
+    layer_tree_host_->DidLoseOutputSurface();
+  }
   client_->DidAbortSwapBuffers();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->DidLoseOutputSurface();
 }
 
 void SingleThreadProxy::DidSwapBuffersOnImplThread() {
+  TRACE_EVENT0("cc", "SingleThreadProxy::DidSwapBuffersOnImplThread");
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->DidSwapBuffers();
   client_->DidPostSwapBuffers();
 }
 
 void SingleThreadProxy::DidSwapBuffersCompleteOnImplThread() {
   TRACE_EVENT0("cc", "SingleThreadProxy::DidSwapBuffersCompleteOnImplThread");
-  client_->DidCompleteSwapBuffers();
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->DidSwapBuffersComplete();
+  layer_tree_host_->DidCompleteSwapBuffers();
+}
+
+void SingleThreadProxy::BeginFrame(const BeginFrameArgs& args) {
+  TRACE_EVENT0("cc", "SingleThreadProxy::BeginFrame");
+  if (scheduler_on_impl_thread_)
+    scheduler_on_impl_thread_->BeginImplFrame(args);
 }
 
-// Called by the legacy scheduling path (e.g. where render_widget does the
-// scheduling)
 void SingleThreadProxy::CompositeImmediately(base::TimeTicks frame_begin_time) {
   TRACE_EVENT0("cc", "SingleThreadProxy::CompositeImmediately");
   DCHECK(Proxy::IsMainThread());
   DCHECK(!layer_tree_host_->output_surface_lost());
 
-  layer_tree_host_->AnimateLayers(frame_begin_time);
-
-  if (PrioritizedResourceManager* contents_texture_manager =
-          layer_tree_host_->contents_texture_manager()) {
-    contents_texture_manager->UnlinkAndClearEvictedBackings();
-    contents_texture_manager->SetMaxMemoryLimitBytes(
-        layer_tree_host_impl_->memory_allocation_limit_bytes());
-    contents_texture_manager->SetExternalPriorityCutoff(
-        layer_tree_host_impl_->memory_allocation_priority_cutoff());
-  }
-
-  scoped_ptr<ResourceUpdateQueue> queue =
-      make_scoped_ptr(new ResourceUpdateQueue);
-  layer_tree_host_->UpdateLayers(queue.get());
-  layer_tree_host_->WillCommit();
-  DoCommit(queue.Pass());
-  layer_tree_host_->DidBeginMainFrame();
+  DoCommit(frame_begin_time);
 
   LayerTreeHostImpl::FrameData frame;
-  if (DoComposite(frame_begin_time, &frame)) {
-    {
-      DebugScopedSetMainThreadBlocked main_thread_blocked(this);
-      DebugScopedSetImplThread impl(this);
-
-      // This CapturePostTasks should be destroyed before
-      // DidCommitAndDrawFrame() is called since that goes out to the embedder,
-      // and we want the embedder to receive its callbacks before that.
-      // NOTE: This maintains consistent ordering with the ThreadProxy since
-      // the DidCommitAndDrawFrame() must be post-tasked from the impl thread
-      // there as the main thread is not blocked, so any posted tasks inside
-      // the swap buffers will execute first.
-      BlockingTaskRunner::CapturePostTasks blocked;
-
-      layer_tree_host_impl_->SwapBuffers(frame);
-    }
-    DidSwapFrame();
-  }
+  DoComposite(frame_begin_time, &frame);
 }
 
 scoped_ptr<base::Value> SingleThreadProxy::AsValue() const {
@@ -403,13 +478,11 @@ void SingleThreadProxy::UpdateBackgroundAnimateTicking() {
       !ShouldComposite() && layer_tree_host_impl_->active_tree()->root_layer());
 }
 
-bool SingleThreadProxy::DoComposite(
-    base::TimeTicks frame_begin_time,
-    LayerTreeHostImpl::FrameData* frame) {
+DrawResult SingleThreadProxy::DoComposite(base::TimeTicks frame_begin_time,
+                                          LayerTreeHostImpl::FrameData* frame) {
   TRACE_EVENT0("cc", "SingleThreadProxy::DoComposite");
   DCHECK(!layer_tree_host_->output_surface_lost());
 
-  bool lost_output_surface = false;
   {
     DebugScopedSetImplThread impl(this);
     base::AutoReset<bool> mark_inside(&inside_draw_, true);
@@ -420,9 +493,11 @@ bool SingleThreadProxy::DoComposite(
     // CanDraw() as well.
     if (!ShouldComposite()) {
       UpdateBackgroundAnimateTicking();
-      return false;
+      return DRAW_ABORTED_CANT_DRAW;
     }
 
+    timing_history_.DidStartDrawing();
+
     layer_tree_host_impl_->Animate(
         layer_tree_host_impl_->CurrentFrameTimeTicks());
     UpdateBackgroundAnimateTicking();
@@ -432,24 +507,42 @@ bool SingleThreadProxy::DoComposite(
       layer_tree_host_impl_->DrawLayers(frame, frame_begin_time);
       layer_tree_host_impl_->DidDrawAllLayers(*frame);
     }
-    lost_output_surface = layer_tree_host_impl_->IsContextLost();
 
     bool start_ready_animations = true;
     layer_tree_host_impl_->UpdateAnimationState(start_ready_animations);
 
     layer_tree_host_impl_->ResetCurrentFrameTimeForNextFrame();
+
+    timing_history_.DidFinishDrawing();
   }
 
-  if (lost_output_surface) {
-    layer_tree_host_->DidLoseOutputSurface();
-    return false;
+  {
+    DebugScopedSetImplThread impl(this);
+
+    if (layer_tree_host_impl_->IsContextLost()) {
+      DidLoseOutputSurfaceOnImplThread();
+    } else {
+      // This CapturePostTasks should be destroyed before
+      // DidCommitAndDrawFrame() is called since that goes out to the embedder,
+      // and we want the embedder to receive its callbacks before that.
+      // NOTE: This maintains consistent ordering with the ThreadProxy since
+      // the DidCommitAndDrawFrame() must be post-tasked from the impl thread
+      // there as the main thread is not blocked, so any posted tasks inside
+      // the swap buffers will execute first.
+      DebugScopedSetMainThreadBlocked main_thread_blocked(this);
+
+      BlockingTaskRunner::CapturePostTasks blocked;
+      layer_tree_host_impl_->SwapBuffers(*frame);
+    }
   }
+  DidCommitAndDrawFrame();
 
-  return true;
+  return DRAW_SUCCESS;
 }
 
-void SingleThreadProxy::DidSwapFrame() {
+void SingleThreadProxy::DidCommitAndDrawFrame() {
   if (next_frame_is_newly_committed_frame_) {
+    DebugScopedSetMainThread main(this);
     next_frame_is_newly_committed_frame_ = false;
     layer_tree_host_->DidCommitAndDrawFrame();
   }
@@ -457,4 +550,112 @@ void SingleThreadProxy::DidSwapFrame() {
 
 bool SingleThreadProxy::CommitPendingForTesting() { return false; }
 
+scoped_ptr<base::Value> SingleThreadProxy::SchedulerAsValueForTesting() {
+  DebugScopedSetImplThread impl(this);
+  if (!scheduler_on_impl_thread_)
+    return make_scoped_ptr(base::Value::CreateNullValue()).Pass();
+  return scheduler_on_impl_thread_->AsValue().Pass();
+}
+
+void SingleThreadProxy::SetNeedsBeginFrame(bool enable) {
+  layer_tree_host_impl_->SetNeedsBeginFrame(enable);
+}
+
+void SingleThreadProxy::WillBeginImplFrame(const BeginFrameArgs& args) {
+  layer_tree_host_impl_->WillBeginImplFrame(args);
+}
+
+void SingleThreadProxy::ScheduledActionSendBeginMainFrame() {
+  TRACE_EVENT0("cc", "SingleThreadProxy::ScheduledActionSendBeginMainFrame");
+  if (defer_commits_) {
+    DCHECK(!commit_was_deferred_);
+    commit_was_deferred_ = true;
+    layer_tree_host_->DidDeferCommit();
+    return;
+  }
+  timing_history_.DidBeginMainFrame();
+
+  DCHECK(scheduler_on_impl_thread_);
+  scheduler_on_impl_thread_->NotifyBeginMainFrameStarted();
+  scheduler_on_impl_thread_->NotifyReadyToCommit();
+}
+
+DrawResult SingleThreadProxy::ScheduledActionDrawAndSwapIfPossible() {
+  DebugScopedSetImplThread impl(this);
+  if (layer_tree_host_impl_->IsContextLost()) {
+    DidCommitAndDrawFrame();
+    return DRAW_SUCCESS;
+  }
+
+  LayerTreeHostImpl::FrameData frame;
+  return DoComposite(layer_tree_host_impl_->CurrentFrameTimeTicks(), &frame);
+}
+
+DrawResult SingleThreadProxy::ScheduledActionDrawAndSwapForced() {
+  NOTREACHED();
+  return INVALID_RESULT;
+}
+
+void SingleThreadProxy::ScheduledActionCommit() {
+  DebugScopedSetMainThread main(this);
+  DoCommit(layer_tree_host_impl_->CurrentFrameTimeTicks());
+}
+
+void SingleThreadProxy::ScheduledActionAnimate() {
+  TRACE_EVENT0("cc", "ScheduledActionAnimate");
+  layer_tree_host_impl_->Animate(
+      layer_tree_host_impl_->CurrentFrameTimeTicks());
+}
+
+void SingleThreadProxy::ScheduledActionUpdateVisibleTiles() {
+  // Impl-side painting only.
+  NOTREACHED();
+}
+
+void SingleThreadProxy::ScheduledActionActivatePendingTree() {
+  // Impl-side painting only.
+  NOTREACHED();
+}
+
+void SingleThreadProxy::ScheduledActionBeginOutputSurfaceCreation() {
+  DebugScopedSetMainThread main(this);
+  DCHECK(scheduler_on_impl_thread_);
+  // If possible, create the output surface in a post task.  Synchronously
+  // creating the output surface makes tests more awkward since this differs
+  // from the ThreadProxy behavior.  However, sometimes there is no
+  // task runner.
+  if (Proxy::MainThreadTaskRunner()) {
+    Proxy::MainThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&SingleThreadProxy::CreateAndInitializeOutputSurface,
+                   weak_factory_.GetWeakPtr()));
+  } else {
+    CreateAndInitializeOutputSurface();
+  }
+}
+
+void SingleThreadProxy::ScheduledActionManageTiles() {
+  // Impl-side painting only.
+  NOTREACHED();
+}
+
+void SingleThreadProxy::DidAnticipatedDrawTimeChange(base::TimeTicks time) {
+}
+
+base::TimeDelta SingleThreadProxy::DrawDurationEstimate() {
+  return timing_history_.DrawDurationEstimate();
+}
+
+base::TimeDelta SingleThreadProxy::BeginMainFrameToCommitDurationEstimate() {
+  return timing_history_.BeginMainFrameToCommitDurationEstimate();
+}
+
+base::TimeDelta SingleThreadProxy::CommitToActivateDurationEstimate() {
+  return timing_history_.CommitToActivateDurationEstimate();
+}
+
+void SingleThreadProxy::DidBeginImplFrameDeadline() {
+  layer_tree_host_impl_->ResetCurrentFrameTimeForNextFrame();
+}
+
 }  // namespace cc
diff --git a/cc/trees/single_thread_proxy.h b/cc/trees/single_thread_proxy.h
index 7ad48b4..fcc04fd 100644
--- a/cc/trees/single_thread_proxy.h
+++ b/cc/trees/single_thread_proxy.h
@@ -10,8 +10,10 @@
 #include "base/time/time.h"
 #include "cc/animation/animation_events.h"
 #include "cc/output/begin_frame_args.h"
+#include "cc/scheduler/scheduler.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "cc/trees/proxy.h"
+#include "cc/trees/proxy_timing_history.h"
 
 namespace cc {
 
@@ -20,7 +22,8 @@ class LayerTreeHost;
 class LayerTreeHostSingleThreadClient;
 
 class CC_EXPORT SingleThreadProxy : public Proxy,
-                    NON_EXPORTED_BASE(LayerTreeHostImplClient) {
+                                    NON_EXPORTED_BASE(LayerTreeHostImplClient),
+                                    SchedulerClient {
  public:
   static scoped_ptr<Proxy> Create(
       LayerTreeHost* layer_tree_host,
@@ -49,6 +52,25 @@ class CC_EXPORT SingleThreadProxy : public Proxy,
   virtual void ForceSerializeOnSwapBuffers() OVERRIDE;
   virtual scoped_ptr<base::Value> AsValue() const OVERRIDE;
   virtual bool CommitPendingForTesting() OVERRIDE;
+  virtual scoped_ptr<base::Value> SchedulerAsValueForTesting() OVERRIDE;
+
+  // SchedulerClient implementation
+  virtual void SetNeedsBeginFrame(bool enable) OVERRIDE;
+  virtual void WillBeginImplFrame(const BeginFrameArgs& args) OVERRIDE;
+  virtual void ScheduledActionSendBeginMainFrame() OVERRIDE;
+  virtual DrawResult ScheduledActionDrawAndSwapIfPossible() OVERRIDE;
+  virtual DrawResult ScheduledActionDrawAndSwapForced() OVERRIDE;
+  virtual void ScheduledActionCommit() OVERRIDE;
+  virtual void ScheduledActionAnimate() OVERRIDE;
+  virtual void ScheduledActionUpdateVisibleTiles() OVERRIDE;
+  virtual void ScheduledActionActivatePendingTree() OVERRIDE;
+  virtual void ScheduledActionBeginOutputSurfaceCreation() OVERRIDE;
+  virtual void ScheduledActionManageTiles() OVERRIDE;
+  virtual void DidAnticipatedDrawTimeChange(base::TimeTicks time) OVERRIDE;
+  virtual base::TimeDelta DrawDurationEstimate() OVERRIDE;
+  virtual base::TimeDelta BeginMainFrameToCommitDurationEstimate() OVERRIDE;
+  virtual base::TimeDelta CommitToActivateDurationEstimate() OVERRIDE;
+  virtual void DidBeginImplFrameDeadline() OVERRIDE;
 
   // LayerTreeHostImplClient implementation
   virtual void UpdateRendererCapabilitiesOnImplThread() OVERRIDE;
@@ -59,7 +81,7 @@ class CC_EXPORT SingleThreadProxy : public Proxy,
   virtual void SetMaxSwapsPendingOnImplThread(int max) OVERRIDE {}
   virtual void DidSwapBuffersOnImplThread() OVERRIDE;
   virtual void DidSwapBuffersCompleteOnImplThread() OVERRIDE;
-  virtual void BeginFrame(const BeginFrameArgs& args) OVERRIDE {}
+  virtual void BeginFrame(const BeginFrameArgs& args) OVERRIDE;
   virtual void OnCanDrawStateChanged(bool can_draw) OVERRIDE;
   virtual void NotifyReadyToActivate() OVERRIDE;
   virtual void SetNeedsRedrawOnImplThread() OVERRIDE;
@@ -79,8 +101,8 @@ class CC_EXPORT SingleThreadProxy : public Proxy,
   virtual void PostDelayedScrollbarFadeOnImplThread(
       const base::Closure& start_fade,
       base::TimeDelta delay) OVERRIDE {}
-  virtual void DidActivatePendingTree() OVERRIDE {}
-  virtual void DidManageTiles() OVERRIDE {}
+  virtual void DidActivatePendingTree() OVERRIDE;
+  virtual void DidManageTiles() OVERRIDE;
   virtual void SetDebugState(const LayerTreeDebugState& debug_state) OVERRIDE {}
 
   // Attempts to create the context and renderer synchronously. Calls
@@ -94,10 +116,11 @@ class CC_EXPORT SingleThreadProxy : public Proxy,
   SingleThreadProxy(LayerTreeHost* layer_tree_host,
                     LayerTreeHostSingleThreadClient* client);
 
-  void DoCommit(scoped_ptr<ResourceUpdateQueue> queue);
-  bool DoComposite(base::TimeTicks frame_begin_time,
-                   LayerTreeHostImpl::FrameData* frame);
-  void DidSwapFrame();
+  void DoCommit(base::TimeTicks frame_begin_time);
+  DrawResult DoComposite(base::TimeTicks frame_begin_time,
+                         LayerTreeHostImpl::FrameData* frame);
+  void DoSwap();
+  void DidCommitAndDrawFrame();
 
   bool ShouldComposite() const;
   void UpdateBackgroundAnimateTicking();
@@ -111,9 +134,18 @@ class CC_EXPORT SingleThreadProxy : public Proxy,
   scoped_ptr<LayerTreeHostImpl> layer_tree_host_impl_;
   RendererCapabilities renderer_capabilities_for_main_thread_;
 
+  // Accessed from both threads.
+  scoped_ptr<Scheduler> scheduler_on_impl_thread_;
+  ProxyTimingHistory timing_history_;
+
   bool next_frame_is_newly_committed_frame_;
 
   bool inside_draw_;
+  bool defer_commits_;
+  bool commit_was_deferred_;
+  bool commit_requested_;
+
+  base::WeakPtrFactory<SingleThreadProxy> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SingleThreadProxy);
 };
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index e16adb9..3dbf0d6 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -454,9 +454,10 @@ void ThreadProxy::SetNextCommitWaitsForActivation() {
 
 void ThreadProxy::SetDeferCommits(bool defer_commits) {
   DCHECK(IsMainThread());
-  DCHECK_NE(main().defer_commits, defer_commits);
-  main().defer_commits = defer_commits;
+  if (main().defer_commits == defer_commits)
+    return;
 
+  main().defer_commits = defer_commits;
   if (main().defer_commits)
     TRACE_EVENT_ASYNC_BEGIN0("cc", "ThreadProxy::SetDeferCommits", this);
   else