Revert of Revert CL 117933003. Re-add resource speculative prefetching code.

chrome/browser/predictors/resource_prefetcher_manager.h

-// Copyright 2014 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_prefetch_common.h"
-#include "chrome/browser/predictors/resource_prefetcher.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 or host (for host
-  // based).
-  void MaybeAddPrefetch(const NavigationID& navigation_id,
-                        PrefetchKeyType key_type,
-                        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<std::string, ResourcePrefetcher*> PrefetcherMap;
-
-  virtual ~ResourcePrefetcherManager();
-
-  // UI Thread. |predictor_| needs to be called on the UI thread.
-  void ResourcePrefetcherFinishedOnUI(
-      const NavigationID& navigation_id,
-      PrefetchKeyType key_type,
-      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_