CSS Paint API: Use counters for interface members

We use count
- CSS.paintWorklet
- PaintWorkletGlobalScope.devicePixelRatio
- PaintWorkletGlobalScope.registerPaint

BUG=578252

Change-Id: I188c980816c3c1f205de0209dd2226e39a7e7475
Reviewed-on: https://chromium-review.googlesource.com/892941
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541794}

third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.idl

@@ -9,6 +9,6 @@
     Global=(Worklet,PaintWorklet),
     RuntimeEnabled=CSSPaintAPI
 ] interface PaintWorkletGlobalScope : WorkletGlobalScope {
-    readonly attribute unrestricted double devicePixelRatio;
-    [RaisesException] void registerPaint(DOMString name, Function paintCtor);
+    [Measure] readonly attribute unrestricted double devicePixelRatio;
+    [Measure, RaisesException] void registerPaint(DOMString name, Function paintCtor);
 };

third_party/WebKit/public/platform/web_feature.mojom

@@ -1874,6 +1874,8 @@ enum WebFeature {
   kRTCConstraintEnableDtlsSrtpTrue = 2382,
   kRTCConstraintEnableDtlsSrtpFalse = 2383,
   kRtcPeerConnectionId = 2384,
+  kV8PaintWorkletGlobalScope_RegisterPaint_Method = 2385,
+  kV8PaintWorkletGlobalScope_DevicePixelRatio_AttributeGetter = 2386,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

tools/metrics/histograms/enums.xml

@@ -17940,6 +17940,9 @@ Called by update_net_error_codes.py.-->
   <int value="2382" label="RTCConstraintEnableDtlsSrtpTrue"/>
   <int value="2383" label="RTCConstraintEnableDtlsSrtpFalse"/>
   <int value="2384" label="RtcPeerConnectionId"/>
+  <int value="2385" label="V8PaintWorkletGlobalScope_RegisterPaint_Method"/>
+  <int value="2386"
+      label="V8PaintWorkletGlobalScope_DevicePixelRatio_AttributeGetter"/>
 </enum>
 
 <enum name="FeedbackSource">