DevTools: [Styles] Add "px" suffix to numbers on arrow up/down

Source/devtools/front_end/elements/MetricsSidebarPane.js

 /*
  * Copyright (C) 2007 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 357 matching lines @@
         /**
          * @param {string} originalValue
          * @param {string} replacementString
          * @this {WebInspector.MetricsSidebarPane}
          */
         function finishHandler(originalValue, replacementString)
         {
             this._applyUserInput(element, replacementString, originalValue, context, false);
         }
 
-        function customNumberHandler(number)
+        /**
+         * @param {string} prefix
+         * @param {number} number
+         * @param {string} suffix
+         * @return {string}
+         */
+        function customNumberHandler(prefix, number, suffix)
         {
             if (styleProperty !== "margin" && number < 0)
                 number = 0;
-            return number;
+            return prefix + number + suffix;
         }
 
         WebInspector.handleElementValueModifications(event, element, finishHandler.bind(this), undefined, customNumberHandler);
     },
 
     editingEnded: function(element, context)
     {
         delete this.originalPropertyData;
         delete this.previousPropertyDataCandidate;
         element.removeEventListener("keydown", context.keyDownHandler, false);
@@ skipping 90 matching lines @@
     },
 
     editingCommitted: function(element, userInput, previousContent, context)
     {
         this.editingEnded(element, context);
         this._applyUserInput(element, userInput, previousContent, context, true);
     },
 
     __proto__: WebInspector.SidebarPane.prototype
 }