DevTools: Support reading CPU profile format on Performance panel

third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js

Index: third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js b/third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js
index 3769b458206fb47843b5be5d5f012f2853414874..0d15c5816f326dcd77c44b39c6f7aeefb43eafa3 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineJSProfile.js
@@ -231,6 +231,86 @@ TimelineModel.TimelineJSProfileProcessor = class {
     }
     return map.get(nativeName) || null;
   }
+
+  /**
+   * @param {*} profile
+   * @return {!Array<!SDK.TracingManager.EventPayload>}
+   */
+  static buildTraceProfileFromCpuProfile(profile) {
+    if (!profile)
+      return [];
+    var events = [];
+    appendEvent('TracingStartedInPage', {'sessionId': '1'}, 0, 0, 'M');
+    var idToNode = new Map();
+    var nodes = profile['nodes'];
+    for (var i = 0; i < nodes.length; ++i)
+      idToNode.set(nodes[i].id, nodes[i]);
+    var programEvent = null;
+    var functionEvent = null;
+    var nextTime = profile.startTime;
+    var currentTime;
+    var samples = profile['samples'];
+    var timeDeltas = profile['timeDeltas'];
+    for (var i = 0; i < samples.length; ++i) {
+      currentTime = nextTime;
+      nextTime += timeDeltas[i];
+      var node = idToNode.get(samples[i]);
+      var name = node.callFrame.functionName;
+      if (name === '(idle)') {
+        closeEvents();
+        continue;
+      }
+      if (!programEvent)
+        programEvent = appendEvent('MessageLoop::RunTask', {}, currentTime, 0, 'X', 'toplevel');
+      if (name === '(program)') {
+        if (functionEvent) {
+          functionEvent.dur = currentTime - functionEvent.ts;
+          functionEvent = null;
+        }
+      } else {
+        // A JS function.
+        if (!functionEvent)
+          functionEvent = appendEvent('FunctionCall', {'sessionId': '1'}, currentTime);
+      }
+    }
+    closeEvents();
+    appendEvent('CpuProfile', {'cpuProfile': profile}, profile.endTime, 0, 'I');
+    return events;
+
+    function closeEvents() {
+      if (programEvent)
+        programEvent.dur = currentTime - programEvent.ts;
+      if (functionEvent)
+        functionEvent.dur = currentTime - functionEvent.ts;
+      programEvent = null;
+      functionEvent = null;
+    }
+
+    /**
+     * @param {string} name
+     * @param {*} data
+     * @param {number} ts
+     * @param {number=} dur
+     * @param {string=} ph
+     * @param {string=} cat
+     * @return {!SDK.TracingManager.EventPayload}
+     */
+    function appendEvent(name, data, ts, dur, ph, cat) {
+      var event = /** @type {!SDK.TracingManager.EventPayload} */ ({
+        cat: cat || 'disabled-by-default-devtools.timeline',
+        name: name,
+        ph: ph || 'X',
+        pid: 1,
+        tid: 1,
+        ts: ts,
+        args: {data: data}
+      });
+      if (dur)
+        event.dur = dur;
+      events.push(event);
+      return event;
+    }
+  }
 };
 
 /** @enum {string} */