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 70 matching lines @@
     : 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) {
+        was_cached(other.was_cached),
+        redirect_url(other.redirect_url) {

[mmenke, 2012/08/01 15:39:53]

Completely unrelated, but while you're here, mind fixing the indentation here? 
Thanks.

[Shishir, 2012/08/01 18:07:49]

Done.

 }
 
 ResourcePrefetchPredictor::URLRequestSummary::~URLRequestSummary() {
 }
 
 ResourcePrefetchPredictor::UrlTableCacheValue::UrlTableCacheValue() {
 }
 
 ResourcePrefetchPredictor::UrlTableCacheValue::~UrlTableCacheValue() {
 }
@@ skipping 244 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
+  // redirect url as a new navigation.

[mmenke, 2012/08/01 10:25:37]

This comment is phrased/placed really oddly, since the code it's just above
exits the function, conditioned on an if statement the comment doesn't mention
at all.  Maybe just add a blank line, to it's clearer it applies to more than
just the code immediately following it?  Or move it below the if statement.

[Shishir, 2012/08/01 18:07:49]

Done.

+  if (response.redirect_url.is_empty())

[mmenke, 2012/08/01 10:25:37]

When does this happen?  Think a comment would be reasonable.

[Shishir, 2012/08/01 18:07:49]

Done.

+    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 395 matching lines @@
                    tables_,
                    urls_to_delete));
 }
 
 void ResourcePrefetchPredictor::SetTablesForTesting(
     scoped_refptr<ResourcePrefetchPredictorTables> tables) {
   tables_ = tables;
 }
 
 }  // namespace predictors