Bug 994117, add method to check if an element has current animations, r=bbirtles

layout/base/nsLayoutUtils.cpp

@@ -330,6 +330,21 @@ nsLayoutUtils::HasAnimations(nsIContent* aContent,
             (aContent, nsGkAtoms::transitionsProperty, aProperty);
 }
 
+bool
+nsLayoutUtils::HasCurrentAnimations(nsIContent* aContent,
+                                    nsIAtom* aAnimationProperty,
+                                    nsPresContext* aPresContext)
+{
+  if (!aContent->MayHaveAnimations())
+    return false;
+
+  TimeStamp now = aPresContext->RefreshDriver()->MostRecentRefresh();
+
+  CommonElementAnimationData* animations =
+    static_cast<CommonElementAnimationData*>(aContent->GetProperty(aAnimationProperty));
+  return (animations && animations->HasCurrentAnimationsAt(now));
+}
+
 static gfxSize
 GetScaleForValue(const nsStyleAnimation::Value& aValue,
                  nsIFrame* aFrame)

layout/base/nsLayoutUtils.h

@@ -1877,6 +1877,15 @@ public:
    */
   static bool HasAnimations(nsIContent* aContent, nsCSSProperty aProperty);
 
+  /**
+   * Returns true if the content node has any current animations or transitions.
+   * A current animation is any animation that has not yet finished playing
+   * including paused animations.
+   */
+  static bool HasCurrentAnimations(nsIContent* aContent,
+                                   nsIAtom* aAnimationProperty,
+                                   nsPresContext* aPresContext);
+
   /**
    * Checks if off-main-thread animations are enabled.
    */

layout/style/AnimationCommon.cpp

@@ -381,6 +381,22 @@ ElementAnimation::IsRunningAt(TimeStamp aTime) const
          iterationsElapsed < mTiming.mIterationCount;
 }
 
+bool
+ElementAnimation::IsCurrentAt(TimeStamp aTime) const
+{
+  if (!mStartTime.IsNull()) {
+    TimeDuration elapsedDuration = ElapsedDurationAt(aTime);
+    ComputedTiming computedTiming =
+      ElementAnimation::GetComputedTimingAt(elapsedDuration, mTiming);
+    if (computedTiming.mPhase == ComputedTiming::AnimationPhase_Before ||
+        computedTiming.mPhase == ComputedTiming::AnimationPhase_Active) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 bool
 ElementAnimation::HasAnimationOfProperty(nsCSSProperty aProperty) const
 {
@@ -675,5 +691,17 @@ CommonElementAnimationData::UpdateAnimationGeneration(nsPresContext* aPresContex
     aPresContext->RestyleManager()->GetAnimationGeneration();
 }
 
+bool
+CommonElementAnimationData::HasCurrentAnimationsAt(TimeStamp aTime)
+{
+  for (uint32_t animIdx = mAnimations.Length(); animIdx-- != 0; ) {
+    if (mAnimations[animIdx]->IsCurrentAt(aTime)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 }
 }

layout/style/AnimationCommon.h

@@ -303,6 +303,7 @@ struct ElementAnimation
 
   bool HasAnimationOfProperty(nsCSSProperty aProperty) const;
   bool IsRunningAt(mozilla::TimeStamp aTime) const;
+  bool IsCurrentAt(mozilla::TimeStamp aTime) const;
 
   // Return the duration, at aTime (or, if paused, mPauseStart), since
   // the *end* of the delay period.  May be negative.
@@ -459,6 +460,10 @@ struct CommonElementAnimationData : public PRCList
   // Update mAnimationGeneration to nsCSSFrameConstructor's count
   void UpdateAnimationGeneration(nsPresContext* aPresContext);
 
+  // Returns true if there is an animation in the before or active phase at
+  // the given time.
+  bool HasCurrentAnimationsAt(mozilla::TimeStamp aTime);
+
   // The refresh time associated with mStyleRule.
   TimeStamp mStyleRuleRefreshTime;