Devtools Animations: Fix invalid memory access crash

Source/core/inspector/InspectorAnimationAgent.cpp

 // Copyright 2014 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 "config.h"
 
 #include "core/inspector/InspectorAnimationAgent.h"
 
 #include "core/animation/Animation.h"
 #include "core/animation/AnimationEffect.h"
@@ skipping 101 matching lines @@
     Decimal decimal = Decimal::fromDouble(keyframe->offset() * 100);
     String offset = decimal.toString();
     offset.append("%");
 
     RefPtr<TypeBuilder::Animation::KeyframeStyle> keyframeObject = TypeBuilder::Animation::KeyframeStyle::create()
         .setOffset(offset)
         .setEasing(keyframe->easing().toString());
     return keyframeObject.release();
 }
 
-static PassRefPtr<TypeBuilder::Animation::KeyframesRule> buildObjectForAnimationKeyframes(const KeyframeEffect* animation)
+static PassRefPtr<TypeBuilder::Animation::KeyframesRule> buildObjectForAnimationKeyframes(const KeyframeEffect* effect)
 {
-    if (!animation->model()->isKeyframeEffectModel())
+    if (!effect || !effect->model() || !effect->model()->isKeyframeEffectModel())
         return nullptr;
-    const KeyframeEffectModelBase* model = toKeyframeEffectModelBase(animation->model());
+    const KeyframeEffectModelBase* model = toKeyframeEffectModelBase(effect->model());
     WillBeHeapVector<RefPtrWillBeMember<Keyframe> > normalizedKeyframes = KeyframeEffectModelBase::normalizedKeyframesForInspector(model->getFrames());
     RefPtr<TypeBuilder::Array<TypeBuilder::Animation::KeyframeStyle> > keyframes = TypeBuilder::Array<TypeBuilder::Animation::KeyframeStyle>::create();
 
     for (const auto& keyframe : normalizedKeyframes) {
         // Ignore CSS Transitions
         if (!keyframe.get()->isStringKeyframe())
             continue;
         const StringKeyframe* stringKeyframe = toStringKeyframe(keyframe.get());
         keyframes->addItem(buildObjectForStringKeyframe(stringKeyframe));
     }
@@ skipping 182 matching lines @@
 #if ENABLE(OILPAN)
     visitor->trace(m_pageAgent);
     visitor->trace(m_domAgent);
     visitor->trace(m_idToAnimation);
     visitor->trace(m_idToAnimationType);
 #endif
     InspectorBaseAgent::trace(visitor);
 }
 
 }