Handle online and offline redirects via interceptor and offline scheme

chrome/browser/android/offline_pages/offline_page_request_redirect_job.h

Index: chrome/browser/android/offline_pages/offline_page_request_redirect_job.h
diff --git a/chrome/browser/android/offline_pages/offline_page_request_redirect_job.h b/chrome/browser/android/offline_pages/offline_page_request_redirect_job.h
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index 0000000000000000000000000000000000000000..ad393decb7ea2ec3eb11ba8c52e154a2503b4b7a
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+++ b/chrome/browser/android/offline_pages/offline_page_request_redirect_job.h
@@ -0,0 +1,62 @@
+// Copyright 2016 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 CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_REQUEST_REDIRECT_JOB_H_
+#define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_REQUEST_REDIRECT_JOB_H_
+
+#include "base/memory/weak_ptr.h"
+#include "net/url_request/url_request_job.h"
+#include "url/gurl.h"
+
+namespace offline_pages {
+
+// A request job that handles the redirection between online URL and offline
+// URL when the offline copy exists.
+class OfflinePageRequestRedirectJob : public net::URLRequestJob {
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // Will be invoked before the request is restarted. The caller can use this
+    // opportunity to set a sepcific state in order to prevent the request from
+    // being intercepted.
+    virtual void OnPrepareToRestart() = 0;
+  };
+
+  OfflinePageRequestRedirectJob(net::URLRequest* request,
+                                net::NetworkDelegate* network_delegate,
+                                Delegate* delegate);
+  ~OfflinePageRequestRedirectJob() override;
+
+  // net::URLRequestJob overrides:
+  void Start() override;
+  void Kill() override;
+  bool IsRedirectResponse(GURL* location, int* http_status_code) override;
+
+  base::WeakPtr<OfflinePageRequestRedirectJob> GetWeakPtr();
+  void FallbackToDefault();
+  void SetRedirectURL(const GURL& url);
+
+ private:
+  enum class State {
+    NOT_DETERMINED,
+    FALLBACK_TO_DEFAULT,
+    DO_REDIRECT
+  };
+
+  void MaybeStartRequest();
+
+  Delegate* delegate_;  // Not owned.
+  bool is_started_;
+  State state_;
+  GURL redirect_url_;
+  base::WeakPtrFactory<OfflinePageRequestRedirectJob> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageRequestRedirectJob);
+};
+
+}  // namespace offline_pages
+
+#endif // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_REQUEST_REDIRECT_JOB_H_