Devtools Animations: Update transition timing on timeline interaction

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 228 matching lines @@
         if (frame->isLocalFrame())
             toLocalFrame(frame)->document()->timeline().setPlaybackRate(playbackRate);
     }
 }
 
 void InspectorAnimationAgent::setCurrentTime(ErrorString*, double currentTime)
 {
     m_pageAgent->inspectedFrame()->document()->timeline().setCurrentTime(currentTime);
 }
 
-void InspectorAnimationAgent::setTiming(ErrorString* errorString, const String& playerId, double duration, double delay)
+void InspectorAnimationAgent::setTiming(ErrorString* errorString, const String& playerId, double duration, double delay, bool isTransition)
 {
     AnimationPlayer* player = assertAnimationPlayer(errorString, playerId);
     if (!player)
         return;
 
-    RefPtrWillBeRawPtr<AnimationNodeTiming> timing = player->source()->timing();
-    UnrestrictedDoubleOrString unrestrictedDuration;
-    unrestrictedDuration.setUnrestrictedDouble(duration);
-    timing->setDuration(unrestrictedDuration);
-    timing->setDelay(delay);
+    if (isTransition) {
+        Animation* animation = toAnimation(player->source());
+        KeyframeEffectModelBase* effect = toKeyframeEffectModelBase(animation->effect());

[dgozman, 2015/03/30 10:38:58]

Can we assert before calling |toKeyframeEffectModelBase| that effect is indeed
keyframe effect?

[samli, 2015/03/30 23:14:17]

Done.

+        ASSERT(effect->isAnimatableValueKeyframeEffectModel());
+        const AnimatableValueKeyframeEffectModel* oldEffect = toAnimatableValueKeyframeEffectModel(effect);
+        const KeyframeVector& frames = oldEffect->getFrames();
+        ASSERT(frames.size() == 3);

[dgozman, 2015/03/30 10:38:58]

Is there any documentation/explanation about the design of transition (being 3
keyframes)? Let's point there in the comment, otherwise this code is too
cryptic.

[samli, 2015/03/30 23:14:17]

Done. There isn't really much to it, except for the fact that delay is
represented by a keyframe instead of "delay" timing parameter in the web
animations API. We have an internal doc discussing why we needed to do this in
the first place, but that isn't necessary for the comprehension of this code.

+        KeyframeVector newFrames;
+        for (int i = 0; i < 3; i++)
+            newFrames.append(toAnimatableValueKeyframe(frames[i]->clone().get()));
+        // Update delay, represented by the distance between the first two keyframes

[dgozman, 2015/03/30 10:38:58]

nit: full stop please.

[samli, 2015/03/30 23:14:17]

Done.

+        newFrames[1]->setOffset(delay / (delay + duration));
+        effect->setFrames(newFrames);
+
+        RefPtrWillBeRawPtr<AnimationNodeTiming> timing = player->source()->timing();
+        UnrestrictedDoubleOrString unrestrictedDuration;
+        unrestrictedDuration.setUnrestrictedDouble(duration + delay);
+        timing->setDuration(unrestrictedDuration);
+    } else {
+        RefPtrWillBeRawPtr<AnimationNodeTiming> timing = player->source()->timing();
+        UnrestrictedDoubleOrString unrestrictedDuration;
+        unrestrictedDuration.setUnrestrictedDouble(duration);
+        timing->setDuration(unrestrictedDuration);
+        timing->setDelay(delay);
+    }
 }
 
 void InspectorAnimationAgent::didCreateAnimationPlayer(AnimationPlayer* player)
 {
     const String& playerId = String::number(player->sequenceNumber());
     if (m_idToAnimationPlayer.get(playerId))
         return;
 
     // Check threshold
     double latestStartTime = 0;
@@ skipping 32 matching lines @@
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_pageAgent);
     visitor->trace(m_domAgent);
     visitor->trace(m_idToAnimationPlayer);
 #endif
     InspectorBaseAgent::trace(visitor);
 }
 
 }