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

chrome/browser/predictors/resource_prefetch_predictor_tab_helper.cc

Index: chrome/browser/predictors/resource_prefetch_predictor_tab_helper.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_tab_helper.cc b/chrome/browser/predictors/resource_prefetch_predictor_tab_helper.cc
deleted file mode 100644
index ec827f11dc067d921bb243088fff54a7e5863d36..0000000000000000000000000000000000000000
--- a/chrome/browser/predictors/resource_prefetch_predictor_tab_helper.cc
+++ /dev/null
@@ -1,62 +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_prefetch_predictor_tab_helper.h"
-
-#include "chrome/browser/predictors/resource_prefetch_predictor.h"
-#include "chrome/browser/predictors/resource_prefetch_predictor_factory.h"
-#include "chrome/browser/profiles/profile.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/load_from_memory_cache_details.h"
-
-DEFINE_WEB_CONTENTS_USER_DATA_KEY(
-    predictors::ResourcePrefetchPredictorTabHelper);
-
-using content::BrowserThread;
-
-namespace predictors {
-
-ResourcePrefetchPredictorTabHelper::ResourcePrefetchPredictorTabHelper(
-    content::WebContents* web_contents)
-    : content::WebContentsObserver(web_contents) {
-}
-
-ResourcePrefetchPredictorTabHelper::~ResourcePrefetchPredictorTabHelper() {
-}
-
-void ResourcePrefetchPredictorTabHelper::DocumentOnLoadCompletedInMainFrame() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-
-  ResourcePrefetchPredictor* predictor =
-      ResourcePrefetchPredictorFactory::GetForProfile(
-          web_contents()->GetBrowserContext());
-  if (!predictor)
-    return;
-
-  NavigationID navigation_id(web_contents());
-  predictor->RecordMainFrameLoadComplete(navigation_id);
-}
-
-void ResourcePrefetchPredictorTabHelper::DidLoadResourceFromMemoryCache(
-    const content::LoadFromMemoryCacheDetails& details) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-
-  ResourcePrefetchPredictor* predictor =
-      ResourcePrefetchPredictorFactory::GetForProfile(
-          web_contents()->GetBrowserContext());
-  if (!predictor)
-    return;
-
-  ResourcePrefetchPredictor::URLRequestSummary summary;
-  summary.navigation_id = NavigationID(web_contents());
-  summary.resource_url = details.url;
-  summary.mime_type = details.mime_type;
-  summary.resource_type =
-      ResourcePrefetchPredictor::GetResourceTypeFromMimeType(
-          details.mime_type, details.resource_type);
-  summary.was_cached = true;
-  predictor->RecordURLResponse(summary);
-}
-
-}  // namespace predictors