[DevTools] Fix responsive design UI issues.

Source/devtools/front_end/sdk/OverridesSupport.js

 /*
  * Copyright (C) 2012 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 490 matching lines @@
 
         this._showRulersChanged();
     },
 
     _userAgentChanged: function()
     {
         if (this._userAgentChangedListenerMuted)
             return;
         var userAgent = this.settings.overrideUserAgent.get() ? this.settings.userAgent.get() : "";
         NetworkAgent.setUserAgentOverride(userAgent);
-        this._updateUserAgentWarningMessage(this._userAgent !== userAgent ? WebInspector.UIString("You might need to reload the page for proper user agent spoofing and viewport rendering.") : "");
+        if (this._userAgent !== userAgent)
+            this._updateUserAgentWarningMessage(WebInspector.UIString("You might need to reload the page for proper user agent spoofing and viewport rendering."));
         this._userAgent = userAgent;
         this.maybeHasActiveOverridesChanged();
     },
 
     _onPageResizerAvailableSizeChanged: function()
     {
         this._deviceMetricsChanged();
     },
 
     _onPageResizerResizeRequested: function(event)
@@ skipping 81 matching lines @@
         function apiCallback(error)
         {
             if (error) {
                 this._updateDeviceMetricsWarningMessage(WebInspector.UIString("Screen emulation is not available on this page."));
                 this._deviceMetricsOverrideAppliedForTest();
                 return;
             }
 
             var overrideDeviceResolution = this.settings.overrideDeviceResolution.get();
             var viewportEnabled = this.settings.emulateViewport.get();
-            this._updateDeviceMetricsWarningMessage(this._overrideDeviceResolution !== overrideDeviceResolution || this._emulateViewportEnabled != viewportEnabled ?
-                WebInspector.UIString("You might need to reload the page for proper user agent spoofing and viewport rendering.") : "");
+            if (this._overrideDeviceResolution !== overrideDeviceResolution || this._emulateViewportEnabled !== viewportEnabled)
+                this._updateDeviceMetricsWarningMessage(WebInspector.UIString("You might need to reload the page for proper user agent spoofing and viewport rendering."));
             this._overrideDeviceResolution = overrideDeviceResolution;
             this._emulateViewportEnabled = viewportEnabled;
             this._deviceMetricsOverrideAppliedForTest();
         }
     },
 
     _deviceMetricsOverrideAppliedForTest: function()
     {
         // Used for sniffing in tests.
     },
@@ skipping 84 matching lines @@
         if (this._hasActiveOverrides !== hasActiveOverrides) {
             this._hasActiveOverrides = hasActiveOverrides;
             this.dispatchEventToListeners(WebInspector.OverridesSupport.Events.HasActiveOverridesChanged);
         }
     },
 
     _onMainFrameNavigated: function()
     {
         this._deviceMetricsChanged();
         this._updateUserAgentWarningMessage("");
+        this._updateDeviceMetricsWarningMessage("");
     },
 
     /**
      * @param {string} warningMessage
      */
     _updateDeviceMetricsWarningMessage: function(warningMessage)
     {
         this._deviceMetricsWarningMessage = warningMessage;
         this.dispatchEventToListeners(WebInspector.OverridesSupport.Events.OverridesWarningUpdated);
     },
@@ skipping 200 matching lines @@
     },
 
     __proto__: WebInspector.Object.prototype
 }
 
 
 /**
  * @type {!WebInspector.OverridesSupport}
  */
 WebInspector.overridesSupport;