[DevTools] Limit responsive design resize request to width/height only.

Source/devtools/front_end/ResponsiveDesignView.js

Index: Source/devtools/front_end/ResponsiveDesignView.js
diff --git a/Source/devtools/front_end/ResponsiveDesignView.js b/Source/devtools/front_end/ResponsiveDesignView.js
index d71b517f2739d06d5746ee692302e9f1c1a90093..76643ff99b96cf183022d28a7ec447e2ceeb6923 100644
--- a/Source/devtools/front_end/ResponsiveDesignView.js
+++ b/Source/devtools/front_end/ResponsiveDesignView.js
@@ -173,7 +173,7 @@ WebInspector.ResponsiveDesignView.prototype = {
         var cssOffset = this._slowPositionStart ? (event.data.currentPosition - this._slowPositionStart) / 10 + this._slowPositionStart - event.data.startPosition : event.data.currentPosition - event.data.startPosition;
         var dipOffset = Math.round(cssOffset * WebInspector.zoomManager.zoomFactor());
         var newSize = Math.max(this._resizeStartSize + dipOffset, 1);
-        var requested = new Size(this._dipWidth, this._dipHeight);
+        var requested = {};
         if (event.target.isVertical())
             requested.height = newSize;
         else