[DevTools] Do not reset page scale on changing zoom.

third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeModel.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @param {function()} updateCallback
  * @implements {WebInspector.TargetManager.Observer}
  */
 WebInspector.DeviceModeModel = function(updateCallback)
@@ skipping 359 matching lines @@
      * @param {!WebInspector.Target} target
      */
     targetRemoved: function(target)
     {
         if (this._target === target)
             this._target = null;
     },
 
     _scaleSettingChanged: function()
     {
-        this._calculateAndEmulate(true);
+        this._calculateAndEmulate(false);
     },
 
     _widthSettingChanged: function()
     {
         this._calculateAndEmulate(false);
     },
 
     _heightSettingChanged: function()
     {
         this._calculateAndEmulate(false);
@@ skipping 220 matching lines @@
         if (!this._target || orientation === this._screenOrientation)
             return;
 
         this._screenOrientation = orientation;
         if (!this._screenOrientation)
             this._target.screenOrientationAgent().clearScreenOrientationOverride();
         else
             this._target.screenOrientationAgent().setScreenOrientationOverride(this._screenOrientation === "landscapePrimary" ? 90 : 0, /** @type {!ScreenOrientationAgent.OrientationType} */ (this._screenOrientation));
     }
 }