[DevTools] Refactor emulated devices modes.

Source/devtools/front_end/emulation/ResponsiveDesignView.js

Index: Source/devtools/front_end/emulation/ResponsiveDesignView.js
diff --git a/Source/devtools/front_end/emulation/ResponsiveDesignView.js b/Source/devtools/front_end/emulation/ResponsiveDesignView.js
index cb2f06beb60e676720cf5fbb454bc3f2c39ea46d..8ae124ee35bf12f112ce6b077640140678d78d9f 100644
--- a/Source/devtools/front_end/emulation/ResponsiveDesignView.js
+++ b/Source/devtools/front_end/emulation/ResponsiveDesignView.js
@@ -734,7 +734,7 @@ WebInspector.ResponsiveDesignView.prototype = {
     {
         if (device && mode) {
             var orientation = device.orientationByName(mode.orientation);
-            this._deviceInsets = new Insets(mode.pageRect.left, mode.pageRect.top, orientation.width - mode.pageRect.left - mode.pageRect.width, orientation.height - mode.pageRect.top - mode.pageRect.height);
+            this._deviceInsets = mode.insets;
         } else {
             this._deviceInsets = new Insets(0, 0, 0, 0);
         }