DevTools: fix execution line update on pretty-print

Source/devtools/front_end/UISourceCodeFrame.js

Index: Source/devtools/front_end/UISourceCodeFrame.js
diff --git a/Source/devtools/front_end/UISourceCodeFrame.js b/Source/devtools/front_end/UISourceCodeFrame.js
index 76a49112246315029923bb05b68f2ed37a23d6e2..2db48874786b23a24adea6fd77a13249d33145e3 100644
--- a/Source/devtools/front_end/UISourceCodeFrame.js
+++ b/Source/devtools/front_end/UISourceCodeFrame.js
@@ -120,11 +120,14 @@ WebInspector.UISourceCodeFrame.prototype = {
         }
     },
 
+    beforeFormattedChange: function() { },
+
     /**
      * @param {!WebInspector.Event} event
      */
     _onFormattedChanged: function(event)
     {
+        this.beforeFormattedChange();
         var content = /** @type {string} */ (event.data.content);
         this._textEditor.setReadOnly(this._uiSourceCode.formatted());
         var selection = this._textEditor.selection();