[DevTools] Access cpu profiler only when JS capability is present.

third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js b/third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js
index 500369d22a8a9a6d40268e8200d6a6901525c188..16045c95bce2cb7a600d8bf9b3af5ba2473de2e1 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/CPUProfilerModel.js
@@ -25,9 +25,9 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+
 /**
  * @implements {Protocol.ProfilerDispatcher}
- * @unrestricted
  */
 SDK.CPUProfilerModel = class extends SDK.SDKModel {
   /**
@@ -36,17 +36,10 @@ SDK.CPUProfilerModel = class extends SDK.SDKModel {
   constructor(target) {
     super(target);
     this._isRecording = false;
+    this._profilerAgent = target.profilerAgent();
     target.registerProfilerDispatcher(this);
-    target.profilerAgent().enable();
-
-    this._configureCpuProfilerSamplingInterval();
-    Common.moduleSetting('highResolutionCpuProfiling')
-        .addChangeListener(this._configureCpuProfilerSamplingInterval, this);
-  }
-
-  _configureCpuProfilerSamplingInterval() {
-    var intervalUs = Common.moduleSetting('highResolutionCpuProfiling').get() ? 100 : 1000;
-    this.target().profilerAgent().setSamplingInterval(intervalUs);
+    this._profilerAgent.enable();
+    this._debuggerModel = /** @type {!SDK.DebuggerModel} */ (target.model(SDK.DebuggerModel));
   }
 
   /**
@@ -80,10 +73,8 @@ SDK.CPUProfilerModel = class extends SDK.SDKModel {
    */
   _dispatchProfileEvent(eventName, id, scriptLocation, title, cpuProfile) {
     // Make sure ProfilesPanel is initialized and CPUProfileType is created.
-    self.runtime.loadModulePromise('profiler').then(_ => {
-      var debuggerModel =
-          /** @type {!SDK.DebuggerModel} */ (SDK.DebuggerModel.fromTarget(this.target()));
-      var debuggerLocation = SDK.DebuggerModel.Location.fromPayload(debuggerModel, scriptLocation);
+    self.runtime.loadModulePromise('profiler').then(() => {
+      var debuggerLocation = SDK.DebuggerModel.Location.fromPayload(this._debuggerModel, scriptLocation);
       var globalId = this.target().id() + '.' + id;
       var data = /** @type {!SDK.CPUProfilerModel.EventData} */ (
           {id: globalId, scriptLocation: debuggerLocation, cpuProfile: cpuProfile, title: title});
@@ -98,10 +89,15 @@ SDK.CPUProfilerModel = class extends SDK.SDKModel {
     return this._isRecording;
   }
 
+  /**
+   * @return {!Promise}

[alph, 2017/02/28 23:59:13]

Why promise? It's a sync function

[dgozman, 2017/03/01 00:18:41]

Correct, removed the promise.

+   */
   startRecording() {
     this._isRecording = true;
-    this.target().profilerAgent().start();
     Host.userMetrics.actionTaken(Host.UserMetrics.Action.ProfilesCPUProfileTaken);
+    var intervalUs = Common.moduleSetting('highResolutionCpuProfiling').get() ? 100 : 1000;
+    this._profilerAgent.setSamplingInterval(intervalUs);
+    return this._profilerAgent.start();
   }
 
   /**
@@ -117,20 +113,32 @@ SDK.CPUProfilerModel = class extends SDK.SDKModel {
       return !error && profile ? profile : null;
     }
     this._isRecording = false;
-    return this.target().profilerAgent().stop(extractProfile);
+    return this._profilerAgent.stop(extractProfile);
   }
 
   /**
-   * @override
+   * @return {!Promise}
+   */
+  startPreciseCoverage() {
+    return this._profilerAgent.startPreciseCoverage();
+  }
+
+  /**
+   * @return {!Promise<!Array<!Protocol.Profiler.ScriptCoverage>>}
+   */
+  takePreciseCoverage() {
+    return this._profilerAgent.takePreciseCoverage((error, coverage) => error ? [] : coverage);
+  }
+
+  /**
+   * @return {!Promise}
    */
-  dispose() {
-    Common.moduleSetting('highResolutionCpuProfiling')
-        .removeChangeListener(this._configureCpuProfilerSamplingInterval, this);
+  stopPreciseCoverage() {
+    return this._profilerAgent.stopPreciseCoverage();
   }
 };
 
-// TODO(dgozman): should be JS.
-SDK.SDKModel.register(SDK.CPUProfilerModel, SDK.Target.Capability.None);
+SDK.SDKModel.register(SDK.CPUProfilerModel, SDK.Target.Capability.JS);
 
 /** @enum {symbol} */
 SDK.CPUProfilerModel.Events = {