Speculative resource prefetching - fixing missing navigations due to server side redirects.

chrome/browser/predictors/resource_prefetch_predictor.cc

 // 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.
 
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 
 #include <map>
 #include <set>
 #include <utility>
 
@@ skipping 66 matching lines @@
       num_resources_assumed_prefetched(25) {
 }
 
 ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary()
     : resource_type(ResourceType::LAST_TYPE),
       was_cached(false) {
 }
 
 ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary(
     const URLRequestSummary& other)
-      : navigation_id(other.navigation_id),
-        resource_url(other.resource_url),
-        resource_type(other.resource_type),
-        mime_type(other.mime_type),
-        was_cached(other.was_cached) {
+        : navigation_id(other.navigation_id),
+          resource_url(other.resource_url),
+          resource_type(other.resource_type),
+          mime_type(other.mime_type),
+          was_cached(other.was_cached),
+          redirect_url(other.redirect_url) {
 }
 
 ResourcePrefetchPredictor::URLRequestSummary::~URLRequestSummary() {
 }
 
 ResourcePrefetchPredictor::UrlTableCacheValue::UrlTableCacheValue() {
 }
 
 ResourcePrefetchPredictor::UrlTableCacheValue::~UrlTableCacheValue() {
 }
@@ skipping 236 matching lines @@
     const URLRequestSummary& response) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // TODO(shishir): The prefreshing will be stopped here.
 }
 
 void ResourcePrefetchPredictor::OnMainFrameRedirect(
     const URLRequestSummary& response) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  // Remove the older navigation.
   inflight_navigations_.erase(response.navigation_id);
+
+  // We do not see another navigation start for a redirect, so record the

[James Hawkins, 2012/08/02 18:17:50]

nit: Don't use pronouns in comments (we); pronouns are ambiguous.

[Shishir, 2012/08/02 18:25:43]

Done.

+  // redirect url as a new navigation.
+
+  // The redirect url may be empty if the url was invalid.
+  if (response.redirect_url.is_empty())
+    return;
+
+  NavigationID navigation_id(response.navigation_id);
+  navigation_id.main_frame_url = response.redirect_url;
+  inflight_navigations_.insert(std::make_pair(
+      navigation_id, std::vector<URLRequestSummary>()));
 }
 
 void ResourcePrefetchPredictor::OnSubresourceResponse(
     const URLRequestSummary& response) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   if (inflight_navigations_.find(response.navigation_id) ==
       inflight_navigations_.end()) {
     return;
   }
@@ skipping 398 matching lines @@
                    tables_,
                    urls_to_delete));
 }
 
 void ResourcePrefetchPredictor::SetTablesForTesting(
     scoped_refptr<ResourcePrefetchPredictorTables> tables) {
   tables_ = tables;
 }
 
 }  // namespace predictors