Unified BeginFrame scheduling

content/browser/renderer_host/display_link_mac.cc

Index: content/browser/renderer_host/display_link_mac.cc
diff --git a/content/browser/renderer_host/display_link_mac.cc b/content/browser/renderer_host/display_link_mac.cc
index b4592a9f3b77832aa0801c6e5acd3bd841ee0244..e848829e60abac0797466de2a8eb0c3d73d0a7cd 100644
--- a/content/browser/renderer_host/display_link_mac.cc
+++ b/content/browser/renderer_host/display_link_mac.cc
@@ -94,6 +94,15 @@ bool DisplayLinkMac::GetVSyncParameters(
   return true;
 }
 
+void DisplayLinkMac::AddObserver(Observer* observer) {
+  StartOrContinueDisplayLink();
+  observer_list_.AddObserver(observer);
+}
+
+void DisplayLinkMac::RemoveObserver(Observer* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
 void DisplayLinkMac::Tick(const CVTimeStamp* cv_time) {
   TRACE_EVENT0("browser", "DisplayLinkMac::GetVSyncParameters");
   base::AutoLock lock(lock_);
@@ -114,6 +123,10 @@ void DisplayLinkMac::Tick(const CVTimeStamp* cv_time) {
   interval_ = base::TimeDelta::FromMicroseconds(
       1000000 * static_cast<int64>(numerator) / denominator);
   timebase_and_interval_valid_ = true;
+
+  FOR_EACH_OBSERVER(Observer,
+                    observer_list_,
+                    OnVSync(timebase_, interval_));
 }
 
 void DisplayLinkMac::StartOrContinueDisplayLink() {