[DevTools] Use device metrics emulation implemented in content.

Source/devtools/front_end/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 16 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 /**
  * @constructor
  */
 WebInspector.OverridesSupport = function()
 {
     this._overridesActive = WebInspector.settings.enableOverridesOnStartup.get();
+    this._deviceMetricsOverridesActive = false;
     this._updateAllOverrides();
 
     WebInspector.settings.overrideUserAgent.addChangeListener(this._userAgentChanged, this);
     WebInspector.settings.userAgent.addChangeListener(this._userAgentChanged, this);
 
     WebInspector.settings.overrideDeviceMetrics.addChangeListener(this._deviceMetricsChanged, this);
     WebInspector.settings.deviceMetrics.addChangeListener(this._deviceMetricsChanged, this);
     WebInspector.settings.deviceFitWindow.addChangeListener(this._deviceMetricsChanged, this);
 
     WebInspector.settings.overrideGeolocation.addChangeListener(this._geolocationPositionChanged, this);
@@ skipping 292 matching lines @@
     },
 
     _userAgentChanged: function()
     {
         NetworkAgent.setUserAgentOverride(this._overridesActive && WebInspector.settings.overrideUserAgent.get() ? WebInspector.settings.userAgent.get() : "");
     },
 
     _deviceMetricsChanged: function()
     {
         var metrics = WebInspector.OverridesSupport.DeviceMetrics.parseSetting(this._overridesActive && WebInspector.settings.overrideDeviceMetrics.get() ? WebInspector.settings.deviceMetrics.get() : "");
-        if (metrics.isValid())
+        if (metrics.isValid()) {
+            var active = metrics.width > 0 && metrics.height > 0;
             PageAgent.setDeviceMetricsOverride(metrics.width, metrics.height, metrics.fontScaleFactor, WebInspector.settings.deviceFitWindow.get());
+            if (active != this._deviceMetricsOverridesActive) {
+                PageAgent.reload(false);
+                this._deviceMetricsOverridesActive = active;
+            }
+        }
     },
 
     _geolocationPositionChanged: function()
     {
         if (!this._overridesActive || !WebInspector.settings.overrideGeolocation.get()) {
             PageAgent.clearGeolocationOverride();
             return;
         }
         var geolocation = WebInspector.OverridesSupport.GeolocationPosition.parseSetting(WebInspector.settings.geolocationOverride.get());
         if (geolocation.error)
@@ skipping 22 matching lines @@
         PageAgent.setEmulatedMedia(this._overridesActive && WebInspector.settings.overrideCSSMedia.get() ? WebInspector.settings.emulatedCSSMedia.get() : "");
         WebInspector.cssModel.mediaQueryResultChanged();
     }
 }
 
 
 /**
  * @type {WebInspector.OverridesSupport}
  */
 WebInspector.overridesSupport;