Attempt to fix the crash in blink Scroll Animator.

third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp

Index: third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp
diff --git a/third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp b/third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp
index 2d73c4776342ba224bd772133e0f9817b2f6aae6..0ecf8b9f98a3360be88cedef6db808244838ff55 100644
--- a/third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp
+++ b/third_party/WebKit/Source/platform/animation/CompositorAnimationPlayer.cpp
@@ -72,8 +72,8 @@ void CompositorAnimationPlayer::NotifyAnimationStarted(
     cc::Animation::TargetProperty targetProperty,
     int group)
 {
-    ASSERT(m_delegate);
-    m_delegate->notifyAnimationStarted((monotonicTime - base::TimeTicks()).InSecondsF(), group);
+    if (m_delegate)

[loyso (OOO), 2016/02/22 23:47:29]

I think, these changes are unrelated to your fix. Could you set them as a
separate, dependent CL? Nevertheless, I don't see how it is connected to
not-calling setAnimationDelegate(nullptr).

[ymalik, 2016/02/23 00:49:33]

The premise of this CL is that we need to call setAnimationDelegate(nullptr) at
the right time (when ScrollAnimator is actually swept away rather than when
~ScrollAnimator is called). So in that case, we need this here so that we don't
crash when a notification comes in after the ScrollAnimator is GCed.

+        m_delegate->notifyAnimationStarted((monotonicTime - base::TimeTicks()).InSecondsF(), group);
 }
 
 void CompositorAnimationPlayer::NotifyAnimationFinished(
@@ -81,8 +81,8 @@ void CompositorAnimationPlayer::NotifyAnimationFinished(
     cc::Animation::TargetProperty targetProperty,
     int group)
 {
-    ASSERT(m_delegate);
-    m_delegate->notifyAnimationFinished((monotonicTime - base::TimeTicks()).InSecondsF(), group);
+    if (m_delegate)
+        m_delegate->notifyAnimationFinished((monotonicTime - base::TimeTicks()).InSecondsF(), group);
 }
 
 void CompositorAnimationPlayer::NotifyAnimationAborted(
@@ -90,8 +90,8 @@ void CompositorAnimationPlayer::NotifyAnimationAborted(
     cc::Animation::TargetProperty targetProperty,
     int group)
 {
-    ASSERT(m_delegate);
-    m_delegate->notifyAnimationAborted((monotonicTime - base::TimeTicks()).InSecondsF(), group);
+    if (m_delegate)
+        m_delegate->notifyAnimationAborted((monotonicTime - base::TimeTicks()).InSecondsF(), group);
 }
 
 } // namespace blink