Add a Content API around BrowserURLHandler.

content/public/browser/browser_url_handler.h

+// Copyright (c) 2011 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_BROWSER_URL_HANDLER_H_
+#define CONTENT_PUBLIC_BROWSER_BROWSER_URL_HANDLER_H_
+#pragma once
+
+#include "content/common/content_export.h"
+
+class GURL;
+
+namespace content {
+class BrowserContext;
+
+// We handle some special browser-level URLs (like "about:version")
+// before they're handed to a renderer.  This lets us do the URL handling
+// on the browser side (which has access to more information than the
+// renderers do) as well as sidestep the risk of exposing data to
+// random web pages (because from the resource loader's perspective, these
+// URL schemes don't exist).
+// BrowserURLHandler manages the list of all special URLs and manages
+// dispatching the URL handling to registered handlers.
+class CONTENT_EXPORT BrowserURLHandler {
+ public:
+  // The type of functions that can process a URL.
+  // If a handler handles |url|, it should :
+  // - optionally modify |url| to the URL that should be sent to the renderer
+  // If the URL is not handled by a handler, it should return false.
+  typedef bool (*URLHandler)(GURL* url,
+                             BrowserContext* browser_context);
+
+  // Returns the null handler for use with |AddHandlerPair()|.
+  static URLHandler null_handler();
+
+  // Returns the singleton instance.
+  static  BrowserURLHandler* GetInstance();
+
+  // RewriteURLIfNecessary gives all registered URLHandlers a shot at processing
+  // the given URL, and modifies it in place.
+  // If the original URL needs to be adjusted if the modified URL is redirected,
+  // this function sets |reverse_on_redirect| to true.
+  virtual void RewriteURLIfNecessary(GURL* url,
+                                     BrowserContext* browser_context,
+                                     bool* reverse_on_redirect) = 0;
+
+  // Add the specified handler pair to the list of URL handlers.
+  virtual void AddHandlerPair(URLHandler handler,
+                              URLHandler reverse_handler) = 0;
+
+ protected:
+  virtual ~BrowserURLHandler() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_BROWSER_URL_HANDLER_H_