DevTools: make timeline respect main target that does not have tracing capability.

Change-Id: I724548b02b574864c482b900376d5a25ba1dab7c
Reviewed-on: https://chromium-review.googlesource.com/1159986Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580414}

third_party/blink/renderer/devtools/front_end/Runtime.js

@@ -971,7 +971,10 @@ Runtime.ExperimentsSupport = class {
    */
   isEnabled(experimentName) {
     this._checkExperiment(experimentName);
-
+    // Check for explicitly disabled experiments first - the code could call setEnable(false) on the experiment enabled
+    // by default and we should respect that.
+    if (Runtime._experimentsSetting()[experimentName] === false)
+      return false;
     if (this._enabledTransiently[experimentName])
       return true;
     if (!this.supportEnabled())

third_party/blink/renderer/devtools/front_end/timeline/TimelineController.js

@@ -13,6 +13,7 @@ Timeline.TimelineController = class {
    * @param {!Timeline.TimelineController.Client} client
    */
   constructor(target, client) {
+    this._target = target;
     this._tracingManager = target.model(SDK.TracingManager);
     this._performanceModel = new Timeline.PerformanceModel();
     this._performanceModel.setMainTarget(target);
@@ -34,7 +35,7 @@ Timeline.TimelineController = class {
    * @return {!SDK.Target}
    */
   mainTarget() {
-    return this._tracingManager.target();
+    return this._target;
   }
 
   /**
@@ -93,8 +94,10 @@ Timeline.TimelineController = class {
    */
   async stopRecording() {
     const tracingStoppedPromises = [];
+    if (this._tracingManager)
       tracingStoppedPromises.push(new Promise(resolve => this._tracingCompleteCallback = resolve));
     tracingStoppedPromises.push(this._stopProfilingOnAllModels());
+    if (this._tracingManager)
       this._tracingManager.stop();
     tracingStoppedPromises.push(SDK.targetManager.resumeAllTargets());
 
@@ -171,14 +174,16 @@ Timeline.TimelineController = class {
    * @param {boolean=} enableJSSampling
    * @return {!Promise}
    */
-  _startRecordingWithCategories(categories, enableJSSampling) {
+  async _startRecordingWithCategories(categories, enableJSSampling) {
     SDK.targetManager.suspendAllTargets();
-    const profilingStartedPromise = enableJSSampling && !Runtime.experiments.isEnabled('timelineTracingJSProfile') ?
-        this._startProfilingOnAllModels() :
-        Promise.resolve();
+    if (enableJSSampling && !Runtime.experiments.isEnabled('timelineTracingJSProfile'))
+      await this._startProfilingOnAllModels();
+    if (!this._tracingManager)
+      return;
+
     const samplingFrequencyHz = Common.moduleSetting('highResolutionCpuProfiling').get() ? 10000 : 1000;
     const options = 'sampling-frequency=' + samplingFrequencyHz;
-    return profilingStartedPromise.then(() => this._tracingManager.start(this, categories, options));
+    return this._tracingManager.start(this, categories, options);
   }
 
   /**
@@ -294,6 +299,20 @@ Timeline.TimelineController = class {
         const pid = mainMetaEvent.thread.process().id();
         const mainCpuProfile = this._cpuProfiles.get(this._tracingManager.target().id());
         this._injectCpuProfileEvent(pid, mainMetaEvent.thread.id(), mainCpuProfile);
+      } else {
+        // Or there was no tracing manager in the main target at all, in this case build the model full
+        // of cpu profiles.
+        // Assign tids equal to the target ordinals for the thread name lookup.
+        // This is a little shaky because targets can disappear, but we will read these tids sooner than
+        // that.
+        // TODO(pfeldman): resolve this.
+        let counter = 1000;
+        for (const pair of this._cpuProfiles) {
+          const target = SDK.targetManager.targetById(pair[0]);
+          const tid = target ? SDK.targetManager.targets().indexOf(target) : ++counter;
+          this._tracingModel.addEvents(
+              TimelineModel.TimelineJSProfileProcessor.buildTraceProfileFromCpuProfile(pair[1], tid));
+        }
       }
     }
 

third_party/blink/renderer/devtools/front_end/timeline/TimelineLoader.js

@@ -221,7 +221,7 @@ Timeline.TimelineLoader = class {
     let traceEvents;
     try {
       const profile = JSON.parse(text);
-      traceEvents = TimelineModel.TimelineJSProfileProcessor.buildTraceProfileFromCpuProfile(profile);
+      traceEvents = TimelineModel.TimelineJSProfileProcessor.buildTraceProfileFromCpuProfile(profile, 1);
     } catch (e) {
       this._reportErrorAndCancelLoading(Common.UIString('Malformed CPU profile format'));
       return;

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

@@ -227,9 +227,10 @@ TimelineModel.TimelineJSProfileProcessor = class {
 
   /**
    * @param {*} profile
+   * @param {number} tid
    * @return {!Array<!SDK.TracingManager.EventPayload>}
    */
-  static buildTraceProfileFromCpuProfile(profile) {
+  static buildTraceProfileFromCpuProfile(profile, tid) {
     if (!profile)
       return [];
     const events = [];
@@ -294,7 +295,7 @@ TimelineModel.TimelineJSProfileProcessor = class {
         name: name,
         ph: ph || 'X',
         pid: 1,
-        tid: 1,
+        tid,
         ts: ts,
         args: {data: data}
       });

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

@@ -180,8 +180,9 @@ TimelineModel.TimelineModel = class {
    * @param {!SDK.TracingModel} tracingModel
    */
   _processGenericTrace(tracingModel) {
-    const browserMainThread =
-        SDK.TracingModel.browserMainThread(tracingModel) || tracingModel.sortedProcesses()[0].sortedThreads()[0];
+    let browserMainThread = SDK.TracingModel.browserMainThread(tracingModel);
+    if (!browserMainThread && tracingModel.sortedProcesses().length)
+      browserMainThread = tracingModel.sortedProcesses()[0].sortedThreads()[0];
     for (const process of tracingModel.sortedProcesses()) {
       for (const thread of process.sortedThreads()) {
         this._processThreadEvents(