Bug 550071 - SVG SMIL: Use refresh driver timestamp, not PR_Now; r=dholbert; a=blocking-betaN

content/smil/nsSMILAnimationController.cpp

@@ -112,6 +112,13 @@ nsSMILAnimationController::Init(nsIDocument* aDoc)
 
   // Keep track of document, so we can traverse its set of animation elements
   mDocument = aDoc;
+  nsRefreshDriver* refreshDriver = GetRefreshDriverForDoc(mDocument);
+  if (refreshDriver) {
+    mStartTime = refreshDriver->MostRecentRefresh();
+  } else {
+    mStartTime = mozilla::TimeStamp::Now();
+  }
+  mCurrentSampleTime = mStartTime;
 
   Begin();
 
@@ -151,8 +158,7 @@ nsSMILAnimationController::Resume(PRUint32 aType)
 nsSMILTime
 nsSMILAnimationController::GetParentTime() const
 {
-  // Our parent time is wallclock time
-  return PR_Now() / PR_USEC_PER_MSEC;
+  return (nsSMILTime)(mCurrentSampleTime - mStartTime).ToMilliseconds();
 }
 
 //----------------------------------------------------------------------
@@ -164,9 +170,13 @@ NS_IMPL_RELEASE(nsSMILAnimationController)
 void
 nsSMILAnimationController::WillRefresh(mozilla::TimeStamp aTime)
 {
-  // XXXdholbert Eventually we should be sampling based on aTime. For now,
-  // though, we keep track of the time on our own, and we just use
-  // nsRefreshDriver for scheduling samples.
+  // Although we never expect aTime to go backwards, when we initialise the
+  // animation controller, if we can't get hold of a refresh driver we
+  // initialise mCurrentSampleTime to Now(). It may be possible that after
+  // doing so we get sampled by a refresh driver whose most recent refresh time
+  // predates when we were initialised, so to be safe we make sure to take the
+  // most recent time here.
+  mCurrentSampleTime = NS_MAX(mCurrentSampleTime, aTime);
   Sample();
 }
 

content/smil/nsSMILAnimationController.h

@@ -70,8 +70,9 @@ class nsIDocument;
 class nsSMILAnimationController : public nsSMILTimeContainer,
                                   public nsARefreshObserver
 {
-public:
+protected:
   nsSMILAnimationController();
+public:
   ~nsSMILAnimationController();
 
   // nsSMILContainer
@@ -190,9 +191,10 @@ protected:
   nsAutoRefCnt mRefCnt;
   NS_DECL_OWNINGTHREAD
 
-  static const PRUint32      kTimerInterval;
   AnimationElementHashtable  mAnimationElementTable;
   TimeContainerHashtable     mChildContainerTable;
+  mozilla::TimeStamp         mCurrentSampleTime;
+  mozilla::TimeStamp         mStartTime;
   PRPackedBool               mResampleNeeded;
   PRPackedBool               mDeferredStartSampling;
 #ifdef DEBUG