DevTools: Do not run CPU profiler on targets with no JS capability.

third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js

Index: third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
index d7ca7c8b726dea720632991c3986066bf2b09eca..6b62e90e3360e5d35dad0ca80d125c85d91208c3 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
@@ -109,7 +109,7 @@ WebInspector.TimelineController.prototype = {
      */
     _startProfilingOnTarget: function(target)
     {
-        return target.profilerAgent().start();
+        return target.hasJSCapability() ? target.profilerAgent().start() : Promise.resolve();
     },
 
     /**
@@ -129,7 +129,7 @@ WebInspector.TimelineController.prototype = {
      */
     _stopProfilingOnTarget: function(target)
     {
-        return target.profilerAgent().stop(this._addCpuProfile.bind(this, target.id()));
+        return target.hasJSCapability() ? target.profilerAgent().stop(this._addCpuProfile.bind(this, target.id())) : Promise.resolve();
     },
 
     /**