Fix double ripple on activated flood fill ripple

ui/views/animation/ink_drop_ripple.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/animation/ink_drop_ripple.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "ui/base/ui_base_switches.h"
@@ skipping 85 matching lines @@
   target_ink_drop_state_ = InkDropState::HIDDEN;
 }
 
 test::InkDropRippleTestApi* InkDropRipple::GetTestApi() {
   return nullptr;
 }
 
 void InkDropRipple::AnimationStartedCallback(
     InkDropState ink_drop_state,
     const ui::CallbackLayerAnimationObserver& observer) {
-  observer_->AnimationStarted(ink_drop_state);
+  if (observer_)
+    observer_->AnimationStarted(ink_drop_state);
 }
 
 bool InkDropRipple::AnimationEndedCallback(
     InkDropState ink_drop_state,
     const ui::CallbackLayerAnimationObserver& observer) {
   if (ink_drop_state == InkDropState::HIDDEN)
     SetStateToHidden();
-  observer_->AnimationEnded(ink_drop_state,
-                            observer.aborted_count()
-                                ? InkDropAnimationEndedReason::PRE_EMPTED
-                                : InkDropAnimationEndedReason::SUCCESS);
+  if (observer_)
+    observer_->AnimationEnded(ink_drop_state,
+                              observer.aborted_count()
+                                  ? InkDropAnimationEndedReason::PRE_EMPTED
+                                  : InkDropAnimationEndedReason::SUCCESS);
   // |this| may be deleted!
   return true;
 }
 
 }  // namespace views