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

chrome/browser/predictors/resource_prefetcher_manager.cc

Index: chrome/browser/predictors/resource_prefetcher_manager.cc
diff --git a/chrome/browser/predictors/resource_prefetcher_manager.cc b/chrome/browser/predictors/resource_prefetcher_manager.cc
deleted file mode 100644
index 15d1b76dcd8ce6f8af472d13732c409a7aa0883e..0000000000000000000000000000000000000000
--- a/chrome/browser/predictors/resource_prefetcher_manager.cc
+++ /dev/null
@@ -1,135 +0,0 @@
-// 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.
-
-#include "chrome/browser/predictors/resource_prefetcher_manager.h"
-
-#include "base/bind.h"
-#include "base/stl_util.h"
-#include "chrome/browser/predictors/resource_prefetch_predictor.h"
-#include "content/public/browser/browser_thread.h"
-#include "net/url_request/url_request.h"
-#include "net/url_request/url_request_context_getter.h"
-
-using content::BrowserThread;
-
-namespace predictors {
-
-ResourcePrefetcherManager::ResourcePrefetcherManager(
-    ResourcePrefetchPredictor* predictor,
-    const ResourcePrefetchPredictorConfig& config,
-    net::URLRequestContextGetter* context_getter)
-    : predictor_(predictor),
-      config_(config),
-      context_getter_(context_getter) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  CHECK(predictor_);
-  CHECK(context_getter_);
-}
-
-ResourcePrefetcherManager::~ResourcePrefetcherManager() {
-  DCHECK(prefetcher_map_.empty())
-      << "Did not call ShutdownOnUIThread or ShutdownOnIOThread. "
-         " Will leak Prefetcher pointers.";
-}
-
-void ResourcePrefetcherManager::ShutdownOnUIThread() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  predictor_ = NULL;
-  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-      base::Bind(&ResourcePrefetcherManager::ShutdownOnIOThread,
-                 this));
-}
-
-void ResourcePrefetcherManager::ShutdownOnIOThread() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-  STLDeleteContainerPairSecondPointers(prefetcher_map_.begin(),
-                                       prefetcher_map_.end());
-}
-
-void ResourcePrefetcherManager::MaybeAddPrefetch(
-    const NavigationID& navigation_id,
-    PrefetchKeyType key_type,
-    scoped_ptr<ResourcePrefetcher::RequestVector> requests) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-
-  // Don't add a duplicate prefetch for the same host or URL.
-  std::string key = key_type == PREFETCH_KEY_TYPE_HOST ?
-      navigation_id.main_frame_url.host() : navigation_id.main_frame_url.spec();
-  if (ContainsKey(prefetcher_map_, key))
-    return;
-
-  ResourcePrefetcher* prefetcher = new ResourcePrefetcher(
-      this, config_, navigation_id, key_type, requests.Pass());
-  prefetcher_map_.insert(std::make_pair(key, prefetcher));
-  prefetcher->Start();
-}
-
-void ResourcePrefetcherManager::MaybeRemovePrefetch(
-    const NavigationID& navigation_id) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-
-  // Look for a URL based prefetch first.
-  PrefetcherMap::iterator it = prefetcher_map_.find(
-      navigation_id.main_frame_url.spec());
-  if (it != prefetcher_map_.end() &&
-      it->second->navigation_id() == navigation_id) {
-    it->second->Stop();
-    return;
-  }
-
-  // No URL based prefetching, look for host based.
-  it = prefetcher_map_.find(navigation_id.main_frame_url.host());
-  if (it != prefetcher_map_.end() &&
-      it->second->navigation_id() == navigation_id) {
-    it->second->Stop();
-  }
-}
-
-void ResourcePrefetcherManager::ResourcePrefetcherFinished(
-    ResourcePrefetcher* resource_prefetcher,
-    ResourcePrefetcher::RequestVector* requests) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-
-  // |predictor_| can only be accessed from the UI thread.
-  scoped_ptr<ResourcePrefetcher::RequestVector> scoped_requests(requests);
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-      base::Bind(&ResourcePrefetcherManager::ResourcePrefetcherFinishedOnUI,
-                 this,
-                 resource_prefetcher->navigation_id(),
-                 resource_prefetcher->key_type(),
-                 base::Passed(&scoped_requests)));
-
-  const GURL& main_frame_url =
-      resource_prefetcher->navigation_id().main_frame_url;
-  const std::string key =
-      resource_prefetcher->key_type() == PREFETCH_KEY_TYPE_HOST ?
-          main_frame_url.host() : main_frame_url.spec();
-  PrefetcherMap::iterator it = prefetcher_map_.find(key);
-  DCHECK(it != prefetcher_map_.end());
-  delete it->second;
-  prefetcher_map_.erase(it);
-}
-
-void ResourcePrefetcherManager::ResourcePrefetcherFinishedOnUI(
-    const NavigationID& navigation_id,
-    PrefetchKeyType key_type,
-    scoped_ptr<ResourcePrefetcher::RequestVector> requests) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  // |predictor_| may have been set to NULL if the predictor is shutting down.
-  if (predictor_) {
-    predictor_->FinishedPrefetchForNavigation(navigation_id,
-                                              key_type,
-                                              requests.release());
-  }
-}
-
-net::URLRequestContext* ResourcePrefetcherManager::GetURLRequestContext() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-
-  return context_getter_->GetURLRequestContext();
-}
-
-}  // namespace predictors