Move of SdchDictionaryFetcher to net.

chrome/browser/net/sdch_dictionary_fetcher.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.
-
-// Support modularity by calling to load a new SDCH filter dictionary.
-// Note that this sort of calling can't be done in the /net directory, as it has
-// no concept of the HTTP cache (which is only visible at the browser level).
-
-#ifndef CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_
-#define CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_
-
-#include <queue>
-#include <set>
-#include <string>
-
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/threading/non_thread_safe.h"
-#include "net/base/sdch_manager.h"
-#include "net/url_request/url_fetcher_delegate.h"
-
-namespace net {
-class URLFetcher;
-class URLRequestContextGetter;
-}  // namespace net
-
-class SdchDictionaryFetcher
-    : public net::URLFetcherDelegate,
-      public net::SdchFetcher,
-      public base::NonThreadSafe {
- public:
-  // Consumer must guarantee that the SdchManager pointer outlives
-  // this object.  The current implementation guarantees this by
-  // the SdchManager owning this object.
-  SdchDictionaryFetcher(net::SdchManager* manager,
-                        net::URLRequestContextGetter* context);
-  virtual ~SdchDictionaryFetcher();
-
-  // Implementation of SdchFetcher class.
-  virtual void Schedule(const GURL& dictionary_url) OVERRIDE;
-  virtual void Cancel() OVERRIDE;
-
- private:
-  // Delay in ms between Schedule and actual download.
-  // This leaves the URL in a queue, which is de-duped, so that there is less
-  // chance we'll try to load the same URL multiple times when a pile of
-  // page subresources (or tabs opened in parallel) all suggest the dictionary.
-  static const int kMsDelayFromRequestTillDownload = 100;
-
-  // Ensure the download after the above delay.
-  void ScheduleDelayedRun();
-
-  // Make sure we're processing (or waiting for) the the arrival of the next URL
-  // in the  |fetch_queue_|.
-  void StartFetching();
-
-  // Implementation of net::URLFetcherDelegate. Called after transmission
-  // completes (either successfully or with failure).
-  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
-
-  net::SdchManager* const manager_;
-
-  // A queue of URLs that are being used to download dictionaries.
-  std::queue<GURL> fetch_queue_;
-  // The currently outstanding URL fetch of a dicitonary.
-  // If this is null, then there is no outstanding request.
-  scoped_ptr<net::URLFetcher> current_fetch_;
-
-  // Always spread out the dictionary fetches, so that they don't steal
-  // bandwidth from the actual page load.  Create delayed tasks to spread out
-  // the download.
-  base::WeakPtrFactory<SdchDictionaryFetcher> weak_factory_;
-  bool task_is_pending_;
-
-  // Althought the SDCH spec does not preclude a server from using a single URL
-  // to load several distinct dictionaries (by telling a client to load a
-  // dictionary from an URL several times), current implementations seem to have
-  // that 1-1 relationship (i.e., each URL points at a single dictionary, and
-  // the dictionary content does not change over time, and hence is not worth
-  // trying to load more than once).  In addition, some dictionaries prove
-  // unloadable only after downloading them (because they are too large?  ...or
-  // malformed?). As a protective element, Chromium will *only* load a
-  // dictionary at most once from a given URL (so that it doesn't waste
-  // bandwidth trying repeatedly).
-  // The following set lists all the dictionary URLs that we've tried to load,
-  // so that we won't try to load from an URL more than once.
-  // TODO(jar): Try to augment the SDCH proposal to include this restiction.
-  std::set<GURL> attempted_load_;
-
-  // Store the system_url_request_context_getter to use it when we start
-  // fetching.
-  scoped_refptr<net::URLRequestContextGetter> context_;
-
-  DISALLOW_COPY_AND_ASSIGN(SdchDictionaryFetcher);
-};
-
-#endif  // CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_