Start splitting out WebUI into an implementation class and an interface that each page implements...

content/public/browser/web_ui_controller.h

+// Copyright (c) 2012 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.
+
+#ifndef CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_
+#define CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/string16.h"
+#include "content/common/content_export.h"
+
+class GURL;
+class RenderViewHost;
+
+namespace base {
+class ListValue;
+}
+
+namespace content {
+
+// A WebUI page is controller by the embedder's WebUIController object. It
+// manages the data source and message handlers.
+class CONTENT_EXPORT WebUIController {
+ public:
+  virtual ~WebUIController() {}
+
+  // Allows the controller to override handling all messages from the page.
+  // Return true if the message handling was overridden.
+  virtual bool OverrideHandleWebUIMessage(const GURL& source_url,
+                                          const std::string& message,
+                                          const base::ListValue& args);
+
+  // Called when RenderView is first created. This is *not* called for every
+  // page load because in some cases a RenderView will be reused. In those
+  // cases, RenderViewReused will be called instead.
+  virtual void RenderViewCreated(RenderViewHost* render_view_host) {}
+
+  // Called when a RenderView is reused to display a page.
+  virtual void RenderViewReused(RenderViewHost* render_view_host) {}
+
+  // Called when this becomes the active WebUI instance for a re-used
+  // RenderView; this is the point at which this WebUI instance will receive
+  // DOM messages instead of the previous WebUI instance.
+  //
+  // If a WebUI instance has code that is usually triggered from a JavaScript
+  // onload handler, this should be overridden to check to see if the web page's
+  // DOM is still intact (e.g., due to a back/forward navigation that remains
+  // within the same page), and if so trigger that code manually since onload
+  // won't be run in that case.
+  virtual void DidBecomeActiveForReusedRenderView() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_