Make SDCH dictionaries persistent across browser restart.

net/url_request/sdch_dictionary_fetcher.h

Index: net/url_request/sdch_dictionary_fetcher.h
diff --git a/net/url_request/sdch_dictionary_fetcher.h b/net/url_request/sdch_dictionary_fetcher.h
index 79d87782e13ece5ef53f671d86409daed0745897..01fb8a092bcdc785e25a4d2babc846131ed3a003 100644
--- a/net/url_request/sdch_dictionary_fetcher.h
+++ b/net/url_request/sdch_dictionary_fetcher.h
@@ -41,15 +41,18 @@ class NET_EXPORT SdchDictionaryFetcher : public URLRequest::Delegate,
       OnDictionaryFetchedCallback;
 
   // The consumer must guarantee that |*context| outlives this object.
-  // |callback| will be called on successful dictionary fetch
-  // requested through Schedule().  |callback| will not be called
-  // after object destruction.
-  SdchDictionaryFetcher(URLRequestContext* context,
-                        const OnDictionaryFetchedCallback& callback);
+  SdchDictionaryFetcher(URLRequestContext* context);
   ~SdchDictionaryFetcher() override;
 
-  // Request a new dictionary fetch.
-  void Schedule(const GURL& dictionary_url);
+  // Request a new dictionary fetch.  The callback will be called
+  // only if the dictionary is successfully fetched.
+  void Schedule(const GURL& dictionary_url,
+                const OnDictionaryFetchedCallback& callback);
+
+  // Request a dictionary fetch from cache only.  The callback will be called
+  // only if the dictionary is successfully fetched.
+  void ScheduleReload(const GURL& dictionary_url,
+                      const OnDictionaryFetchedCallback& callback);
 
   // Cancel any in-progress requests.
   void Cancel();
@@ -67,6 +70,30 @@ class NET_EXPORT SdchDictionaryFetcher : public URLRequest::Delegate,
     STATE_REQUEST_COMPLETE,
   };
 
+  struct QueuedInfo {
+    const GURL url;
+    bool download_only_from_cache;
+    OnDictionaryFetchedCallback callback;
+
+    QueuedInfo();
+    QueuedInfo(const GURL& url,
+               bool download_only_from_cache,
+               const OnDictionaryFetchedCallback& callback);
+    QueuedInfo(const QueuedInfo& rhs) = default;
+    QueuedInfo& operator=(const QueuedInfo& rhs) = default;
+
+    ~QueuedInfo();
+  };
+
+  // Schedule implementation.
+  void ScheduleInternal(const GURL& dictionary_url,
+                        bool reload,
+                        const OnDictionaryFetchedCallback& callback);
+
+  // Null out the current request and push the state machine to the
+  // next request, if any.
+  void ResetRequest();
+
   // State machine implementation.
   int DoLoop(int rv);
   int DoDispatchRequest(int rv);
@@ -78,12 +105,15 @@ class NET_EXPORT SdchDictionaryFetcher : public URLRequest::Delegate,
   bool in_loop_;
 
   // A queue of URLs that are being used to download dictionaries.
-  std::queue<GURL> fetch_queue_;
+  // |fetch_queue_[n].second| indicated whether the download should occur
+  // only from cache.
+  std::queue<QueuedInfo> fetch_queue_;
 
-  // The request and buffer used for getting the current dictionary
-  // Both are null when a fetch is not in progress.
+  // The request, buffer, and consumer supplied data used for getting
+  // the current dictionary.  All are null when a fetch is not in progress.
   scoped_ptr<URLRequest> current_request_;
   scoped_refptr<IOBuffer> buffer_;
+  OnDictionaryFetchedCallback current_callback_;
 
   // The currently accumulating dictionary.
   std::string dictionary_;
@@ -107,8 +137,6 @@ class NET_EXPORT SdchDictionaryFetcher : public URLRequest::Delegate,
   // use while fetching.
   URLRequestContext* const context_;
 
-  const OnDictionaryFetchedCallback dictionary_fetched_callback_;
-
   base::WeakPtrFactory<SdchDictionaryFetcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SdchDictionaryFetcher);