Add cc option to non-lazily disable vsync notification

The option will be used by Android WebView using synchronous compositor
which requires this behavior that conflicts with other platforms.

BUG=

Review URL: https://chromiumcodereview.appspot.com/14898002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198510 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 55 insertions, 11 deletions

diff --git a/cc/scheduler/vsync_time_source.cc b/cc/scheduler/vsync_time_source.cc
index 75314fb..206e2376 100644
--- a/cc/scheduler/vsync_time_source.cc
+++ b/cc/scheduler/vsync_time_source.cc
@@ -4,18 +4,22 @@
 
 #include "cc/scheduler/vsync_time_source.h"
 
+#include "base/logging.h"
+
 namespace cc {
 
 scoped_refptr<VSyncTimeSource> VSyncTimeSource::Create(
-    VSyncProvider* vsync_provider) {
-  return make_scoped_refptr(new VSyncTimeSource(vsync_provider));
+    VSyncProvider* vsync_provider, NotificationDisableOption option) {
+  return make_scoped_refptr(new VSyncTimeSource(vsync_provider, option));
 }
 
-VSyncTimeSource::VSyncTimeSource(VSyncProvider* vsync_provider)
+VSyncTimeSource::VSyncTimeSource(
+    VSyncProvider* vsync_provider, NotificationDisableOption option)
     : active_(false),
       notification_requested_(false),
       vsync_provider_(vsync_provider),
-      client_(NULL) {}
+      client_(NULL),
+      disable_option_(option) {}
 
 VSyncTimeSource::~VSyncTimeSource() {}
 
@@ -27,13 +31,14 @@ void VSyncTimeSource::SetActive(bool active) {
   if (active_ == active)
     return;
   active_ = active;
-  // The notification will be lazily disabled in the callback to ensure
-  // we get notified of the frame immediately following a quick on-off-on
-  // transition.
   if (active_ && !notification_requested_) {
     notification_requested_ = true;
     vsync_provider_->RequestVSyncNotification(this);
   }
+  if (!active_ && disable_option_ == DISABLE_SYNCHRONOUSLY) {
+    notification_requested_ = false;
+    vsync_provider_->RequestVSyncNotification(NULL);
+  }
 }
 
 bool VSyncTimeSource::Active() const {
@@ -55,7 +60,9 @@ void VSyncTimeSource::SetTimebaseAndInterval(base::TimeTicks,
 
 void VSyncTimeSource::DidVSync(base::TimeTicks frame_time) {
   last_tick_time_ = frame_time;
-  if (!active_) {
+  if (disable_option_ == DISABLE_SYNCHRONOUSLY) {
+    DCHECK(active_);
+  } else if (!active_) {
     if (notification_requested_) {
       notification_requested_ = false;
       vsync_provider_->RequestVSyncNotification(NULL);
diff --git a/cc/scheduler/vsync_time_source.h b/cc/scheduler/vsync_time_source.h
index 910168f..4cd0441 100644
--- a/cc/scheduler/vsync_time_source.h
+++ b/cc/scheduler/vsync_time_source.h
@@ -33,7 +33,16 @@ class VSyncProvider {
 // external vsync signal.
 class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
  public:
-  static scoped_refptr<VSyncTimeSource> Create(VSyncProvider* vsync_provider);
+  enum NotificationDisableOption {
+    // The notification will be lazily disabled in the callback to ensure
+    // we get notified of the frame immediately following a quick on-off-on
+    // transition.
+    DISABLE_ON_NEXT_TICK,
+    DISABLE_SYNCHRONOUSLY
+  };
+
+  static scoped_refptr<VSyncTimeSource> Create(
+      VSyncProvider* vsync_provider, NotificationDisableOption option);
 
   // TimeSource implementation
   virtual void SetClient(TimeSourceClient* client) OVERRIDE;
@@ -48,7 +57,8 @@ class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
   virtual void DidVSync(base::TimeTicks frame_time) OVERRIDE;
 
  protected:
-  explicit VSyncTimeSource(VSyncProvider* vsync_provider);
+  explicit VSyncTimeSource(VSyncProvider* vsync_provider,
+                           NotificationDisableOption option);
   virtual ~VSyncTimeSource();
 
   base::TimeTicks last_tick_time_;
@@ -58,6 +68,7 @@ class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
 
   VSyncProvider* vsync_provider_;
   TimeSourceClient* client_;
+  NotificationDisableOption disable_option_;
 
   DISALLOW_COPY_AND_ASSIGN(VSyncTimeSource);
 };
diff --git a/cc/scheduler/vsync_time_source_unittest.cc b/cc/scheduler/vsync_time_source_unittest.cc
index d652017..4834630 100644
--- a/cc/scheduler/vsync_time_source_unittest.cc
+++ b/cc/scheduler/vsync_time_source_unittest.cc
@@ -32,7 +32,9 @@ class FakeVSyncProvider : public VSyncProvider {
 
 class VSyncTimeSourceTest : public testing::Test {
  public:
-  VSyncTimeSourceTest() : timer_(VSyncTimeSource::Create(&provider_)) {
+  VSyncTimeSourceTest()
+      : timer_(VSyncTimeSource::Create(
+          &provider_, VSyncTimeSource::DISABLE_ON_NEXT_TICK)) {
     timer_->SetClient(&client_);
   }
 
@@ -80,6 +82,30 @@ TEST_F(VSyncTimeSourceTest, NotificationDisabledLazily) {
   EXPECT_FALSE(client_.TickCalled());
 }
 
+TEST_F(VSyncTimeSourceTest, NotificationDisabledImmediatelyForSetting) {
+  timer_ = VSyncTimeSource::Create(&provider_,
+                                   VSyncTimeSource::DISABLE_SYNCHRONOUSLY);
+  timer_->SetClient(&client_);
+  base::TimeTicks frame_time = base::TimeTicks::Now();
+
+  // Enable timer and trigger sync once.
+  timer_->SetActive(true);
+  EXPECT_TRUE(provider_.IsVSyncNotificationEnabled());
+  provider_.Trigger(frame_time);
+  EXPECT_TRUE(client_.TickCalled());
+
+  // Disable timer should disable vsync notification immediately.
+  timer_->SetActive(false);
+  EXPECT_FALSE(provider_.IsVSyncNotificationEnabled());
+
+  // Enable again and timer can be ticked again.
+  client_.Reset();
+  timer_->SetActive(true);
+  EXPECT_TRUE(provider_.IsVSyncNotificationEnabled());
+  provider_.Trigger(frame_time);
+  EXPECT_TRUE(client_.TickCalled());
+}
+
 TEST_F(VSyncTimeSourceTest, ValidNextTickTime) {
   base::TimeTicks frame_time = base::TimeTicks::Now();
   base::TimeDelta interval = base::TimeDelta::FromSeconds(1);