DevTools: disable clear button on Performance panel during recording.

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

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 196 matching lines @@
   _createSettingCheckbox(setting, tooltip) {
     const checkboxItem = new UI.ToolbarSettingCheckbox(setting, tooltip);
     this._recordingOptionUIControls.push(checkboxItem);
     return checkboxItem;
   }
 
   _populateToolbar() {
     // Record
     this._panelToolbar.appendToolbarItem(UI.Toolbar.createActionButton(this._toggleRecordAction));
     this._panelToolbar.appendToolbarItem(UI.Toolbar.createActionButtonForId('main.reload'));
-    var clearButton = new UI.ToolbarButton(Common.UIString('Clear'), 'largeicon-clear');
-    clearButton.addEventListener(UI.ToolbarButton.Events.Click, () => this._clear());
-    this._panelToolbar.appendToolbarItem(clearButton);
+    this._clearButton = new UI.ToolbarButton(Common.UIString('Clear'), 'largeicon-clear');
+    this._clearButton.addEventListener(UI.ToolbarButton.Events.Click, () => this._clear());
+    this._panelToolbar.appendToolbarItem(this._clearButton);
     this._panelToolbar.appendSeparator();
 
     // View
     this._panelToolbar.appendSeparator();
     this._showScreenshotsToolbarCheckbox =
         this._createSettingCheckbox(this._showScreenshotsSetting, Common.UIString('Capture screenshots'));
     this._panelToolbar.appendToolbarItem(this._showScreenshotsToolbarCheckbox);
 
     this._showMemoryToolbarCheckbox =
         this._createSettingCheckbox(this._showMemorySetting, Common.UIString('Show memory timeline'));
@@ skipping 316 matching lines @@
   }
 
   _onSuspendStateChanged() {
     this._updateTimelineControls();
   }
 
   _updateTimelineControls() {
     var state = Timeline.TimelinePanel.State;
     this._toggleRecordAction.setToggled(this._state === state.Recording);
     this._toggleRecordAction.setEnabled(this._state === state.Recording || this._state === state.Idle);
+    this._clearButton.setEnabled(this._state === state.Idle);
     this._panelToolbar.setEnabled(this._state !== state.Loading);
     this._dropTarget.setEnabled(this._state === state.Idle);
   }
 
   _toggleRecording() {
     if (this._state === Timeline.TimelinePanel.State.Idle)
       this._startRecording(true);
     else if (this._state === Timeline.TimelinePanel.State.Recording)
       this._stopRecording();
   }
@@ skipping 722 matching lines @@
         return true;
       case 'timeline.jump-to-next-frame':
         panel._jumpToFrame(1);
         return true;
     }
     return false;
   }
 };
 
 Timeline.TimelinePanel._traceProviderSettingSymbol = Symbol('traceProviderSetting');