DevTools: Mangle ProfileChunk events' id

The id is process scoped so mangle it with pid to get a unique id.

Change-Id: I681bf76f1b01c946287c247257c911a326cbced5
Reviewed-on: https://chromium-review.googlesource.com/1123322Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572061}

third_party/blink/renderer/devtools/front_end/sdk/TracingModel.js

@@ -248,19 +248,20 @@ SDK.TracingModel = class {
    * @param {!SDK.TracingModel.Event} event
    */
   _addSampleEvent(event) {
-    const group = this._profileGroups.get(event.id);
+    const id = `${event.thread.process().id()}:${event.id}`;
+    const group = this._profileGroups.get(id);
     if (group)
       group._addChild(event);
     else
-      this._profileGroups.set(event.id, new SDK.TracingModel.ProfileEventsGroup(event));
+      this._profileGroups.set(id, new SDK.TracingModel.ProfileEventsGroup(event));
   }
 
   /**
-   * @param {string} id
+   * @param {!SDK.TracingModel.Event} event
    * @return {?SDK.TracingModel.ProfileEventsGroup}
    */
-  profileGroup(id) {
-    return this._profileGroups.get(id) || null;
+  profileGroup(event) {
+    return this._profileGroups.get(`${event.thread.process().id()}:${event.id}`) || null;
   }
 
   /**

third_party/blink/renderer/devtools/front_end/timeline_model/TimelineModel.js

@@ -429,7 +429,7 @@ TimelineModel.TimelineModel = class {
       cpuProfileEvent = events.find(e => e.name === TimelineModel.TimelineModel.RecordType.Profile);
       if (!cpuProfileEvent)
         return null;
-      const profileGroup = tracingModel.profileGroup(cpuProfileEvent.id);
+      const profileGroup = tracingModel.profileGroup(cpuProfileEvent);
       if (!profileGroup) {
         Common.console.error('Invalid CPU profile format.');
         return null;