Devtools Animations: Support multiple frames in the animation timeline

Source/devtools/protocol.json

Index: Source/devtools/protocol.json
diff --git a/Source/devtools/protocol.json b/Source/devtools/protocol.json
index c91580bfc73618a83779b68b3c586f41c618b284..e1b8ab932e342df25dcdc700193218e0de67431d 100644
--- a/Source/devtools/protocol.json
+++ b/Source/devtools/protocol.json
@@ -4818,11 +4818,16 @@
         "hidden": true,
         "types": [
             {
+                "id": "AnimationPlayerId",
+                "type": "string",
+                "description": "Unique AnimationPlayer identifier."
+            },
+            {
                 "id": "AnimationPlayer",
                 "type": "object",
                 "hidden": true,
                 "properties": [
-                    { "name": "id", "type": "string", "description": "<code>AnimationPlayer</code>'s id." },
+                    { "name": "id", "$ref": "AnimationPlayerId", "description": "<code>AnimationPlayer</code>'s id." },
                     { "name": "pausedState", "type": "boolean", "hidden": "true", "description": "<code>AnimationPlayer</code>'s internal paused state." },
                     { "name": "playState", "type": "string", "description": "<code>AnimationPlayer</code>'s play state." },
                     { "name": "playbackRate", "type": "number", "description": "<code>AnimationPlayer</code>'s playback rate." },
@@ -4871,6 +4876,15 @@
                     { "name": "easing", "type": "string", "description": "<code>AnimationNode</code>'s timing function." }
                 ],
                 "description": "Keyframe Style"
+            },
+            {
+                "id": "AnimationStartTime",
+                "type": "object",
+                "properties": [
+                    { "name": "id", "$ref": "AnimationPlayerId", "description": "<code>AnimationPlayer</code>'s id." },
+                    { "name": "startTime", "type": "number", "description": "Updated normalized <code>AnimationPlayer</code>'s start time." }

[pfeldman, 2015/04/03 09:19:41]

Is this monotonicallyIncreasing time?

[samli, 2015/04/03 09:56:00]

Yes.

[pfeldman, 2015/04/03 10:36:49]

Why is it called normalized then?

[samli, 2015/04/03 11:31:32]

Normalise means to "bring to a standard". We convert relative timeline times to
a standard interface of time. I think it's a reasonable name.

+                ],
+                "description": "Map from animation id to animation start time"
             }
         ],
         "commands": [
@@ -4902,19 +4916,32 @@
                 "parameters": [
                     { "name": "playbackRate", "type": "number", "description": "Playback rate for animations on page" }
                 ],
+                "returns": [
+                    { "name": "animationStartTimes", "type": "array", "items": { "$ref": "AnimationStartTime" }, "description": "List of updated animation start times." }

[pfeldman, 2015/04/03 10:36:49]

So why do you want to collect all start times upon setPlaybackRate and
setCurrentTimes? When does the start time of the animation player change?

[samli, 2015/04/03 11:31:32]

Conceptual start time is always relative to timeline time. When we manipulate
playback rate of a timeline the current time of the timeline does not change.
Old monotonic values are invalidated since they cannot be converted back to
timeline times since the timeline 'scaled' relative to monotonic time.

When seeking a timeline, we are effectively shifting the timeline relative to
monotonic time. This invalidates the start times we sent earlier.

In both cases, the original monotonic start times no longer reference the right
time in the timelines so we need to update the start times.

+                ],
                 "description": "Sets the playback rate of the document timeline."
             },
             {
                 "name": "setCurrentTime",
                 "parameters": [
-                    { "name": "currentTime", "type": "number", "description": "Current time for the page animation timeline" }
+                    { "name": "normalizedCurrentTime", "type": "number", "description": "Current time for the page animation timeline" }

[pfeldman, 2015/04/03 09:19:41]

Is this monotonicallyIncreasing time?

[samli, 2015/04/03 09:56:00]

Yes

+                ],
+                "returns": [
+                    { "name": "animationStartTimes", "type": "array", "items": { "$ref": "AnimationStartTime" }, "description": "List of updated animation start times." }
                 ],
                 "description": "Sets the current time of the document timeline."
             },
             {
+                "name": "seekTimeline",
+                "parameters": [
+                    { "name": "timeDelta", "type": "number", "description": "Time delta in milliseconds to seek animation timelines" }
+                ],
+                "description": "Seek animation timelines by a ms time delta."
+            },
+            {
                 "name": "setTiming",
                 "parameters": [
-                    { "name": "playerId", "type": "string", "description": "AnimationPlayer id." },
+                    { "name": "playerId", "$ref": "AnimationPlayerId", "description": "AnimationPlayer id." },
                     { "name": "duration", "type": "number", "description": "Duration of the animation." },
                     { "name": "delay", "type": "number", "description": "Delay of the animation." }
                 ],