DevTools: migrate sidebar pane's titleElement to use Toolbar.

Source/devtools/front_end/extensions/ExtensionPanel.js

Index: Source/devtools/front_end/extensions/ExtensionPanel.js
diff --git a/Source/devtools/front_end/extensions/ExtensionPanel.js b/Source/devtools/front_end/extensions/ExtensionPanel.js
index 6502a903178e48eba3a9327af2b2824d824bf0a9..1eb7179af4bedd73747812a9ccef07cf40a3c431 100644
--- a/Source/devtools/front_end/extensions/ExtensionPanel.js
+++ b/Source/devtools/front_end/extensions/ExtensionPanel.js
@@ -251,9 +251,9 @@ WebInspector.ExtensionSidebarPane.prototype = {
             this._extensionView.detach(true);
 
         this._extensionView = new WebInspector.ExtensionView(this._server, this._id, url, "extension fill");
-        this._extensionView.show(this.bodyElement);
+        this._extensionView.show(this.element);
 
-        if (!this.bodyElement.style.height)
+        if (!this.element.style.height)
             this.setHeight("150px");
     },
 
@@ -262,7 +262,7 @@ WebInspector.ExtensionSidebarPane.prototype = {
      */
     setHeight: function(height)
     {
-        this.bodyElement.style.height = height;
+        this.element.style.height = height;
     },
 
     /**
@@ -289,7 +289,7 @@ WebInspector.ExtensionSidebarPane.prototype = {
             delete this._extensionView;
         }
         this._objectPropertiesView = new WebInspector.ExtensionNotifierView(this._server, this._id);
-        this._objectPropertiesView.show(this.bodyElement);
+        this._objectPropertiesView.show(this.element);
     },
 
     /**