Adds speculative prefetching of resources.

chrome/browser/predictors/resource_prefetcher_manager.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 CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_MANAGER_H_
+#define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_MANAGER_H_
+
+#include <map>
+
+#include "base/memory/ref_counted.h"
+#include "chrome/browser/predictors/resource_prefetcher.h"
+#include "chrome/browser/predictors/resource_prefetch_common.h"
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace predictors {
+
+struct NavigationID;
+class ResourcePrefetchPredictor;
+
+// Manages prefetches for multple navigations.
+//  - Created and owned by the resource prefetch predictor.
+//  - Needs to be refcounted as it is de-referenced on two different threads.
+//  - Created on the UI thread, but most functions are called in the IO thread.
+//  - Will only allow one inflight prefresh per main frame URL.
+class ResourcePrefetcherManager
+    :  public ResourcePrefetcher::Delegate,
+       public base::RefCountedThreadSafe<ResourcePrefetcherManager> {
+ public:
+  // The |predictor| should be alive till ShutdownOnIOThread is called.
+  ResourcePrefetcherManager(ResourcePrefetchPredictor* predictor,
+                            const ResourcePrefetchPredictorConfig& config,
+                            net::URLRequestContextGetter* getter);
+
+  // UI thread.
+  void ShutdownOnUIThread();
+
+  // --- IO Thread methods.
+
+  // The prefetchers need to be deleted on the IO thread.
+  void ShutdownOnIOThread();
+
+  // Will create a new ResourcePrefetcher for the main frame url of the input
+  // navigation if there isn't one already for the same URL.
+  void MaybeAddPrefetch(const NavigationID& navigation_id,
+                        scoped_ptr<ResourcePrefetcher::RequestVector> requests);
+
+  // Stops the ResourcePrefetcher for the input navigation, if one was in
+  // progress.
+  void MaybeRemovePrefetch(const NavigationID& navigation_id);
+
+  // ResourcePrefetcher::Delegate methods.
+  virtual void ResourcePrefetcherFinished(
+      ResourcePrefetcher* prefetcher,
+      ResourcePrefetcher::RequestVector* requests) OVERRIDE;
+  virtual net::URLRequestContext* GetURLRequestContext() OVERRIDE;
+
+ private:
+  friend class base::RefCountedThreadSafe<ResourcePrefetcherManager>;
+  friend class MockResourcePrefetcherManager;
+
+  typedef std::map<GURL, ResourcePrefetcher*> PrefetcherMap;
+
+  virtual ~ResourcePrefetcherManager();
+
+  // UI Thread. |predictor_| needs to be called on the UI thread.
+  void ResourcePrefetcherFinishedOnUI(
+      const NavigationID& navigation_id,
+      scoped_ptr<ResourcePrefetcher::RequestVector> requests);
+
+  ResourcePrefetchPredictor* predictor_;
+  const ResourcePrefetchPredictorConfig config_;
+  net::URLRequestContextGetter* const context_getter_;
+
+  PrefetcherMap prefetcher_map_;  // Owns the ResourcePrefetcher pointers.
+
+  DISALLOW_COPY_AND_ASSIGN(ResourcePrefetcherManager);
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_MANAGER_H_