Implement PrerenderManager::AddPrerenderForOffline()

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index 3bc6d9cede0a50e42322ca4d469d7d37971711cc..06cdb24059b36470df1226986d7ccb4f3ca4bc5a 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -325,6 +325,14 @@ PrerenderHandle* PrerenderManager::AddPrerenderForInstant(
                       session_storage_namespace);
 }
 
+PrerenderHandle* PrerenderManager::AddPrerenderForOffline(
+    const GURL& url,
+    content::SessionStorageNamespace* session_storage_namespace,
+    const gfx::Size& size) {
+  return AddPrerender(ORIGIN_OFFLINE, url, content::Referrer(), size,
+                      session_storage_namespace);
+}
+
 void PrerenderManager::CancelAllPrerenders() {
   DCHECK(CalledOnValidThread());
   while (!active_prerenders_.empty()) {
@@ -532,6 +540,9 @@ WebContents* PrerenderManager::SwapInternal(
     ScheduleDeleteOldWebContents(old_web_contents, NULL);
   }
 
+  // Offline originated prerenders should never ever be swapped-in.
+  CHECK_NE(ORIGIN_OFFLINE, prerender_contents->origin());

[pasko, 2016/04/25 11:29:11]

This comment does not propose to change anything, just thoughts and sharing
common hopefully-wisdom:

Just as mmenke@ I am not a fan of CHECKs, so FindPrerenderData() not returning
stuff with offline origin would be safer, though it'd look 

If we see a CHECK in crash reports, we do not have much context with it. I think
what we would do is patch FindPrerenderData() when/if this happens. Let's see.

[gabadie, 2016/04/25 12:35:11]

I have uploaded a new CL that removed that CHECK, but added a test that
FindPrerenderData() no longer find offline originated prerenders.

+
   // TODO(cbentzel): Should prerender_contents move to the pending delete
   //                 list, instead of deleting directly here?
   AddToHistory(prerender_contents.get());
@@ -956,7 +967,8 @@ PrerenderHandle* PrerenderManager::AddPrerender(
   // histogram tracking.
   histograms_->RecordPrerender(origin, url_arg);
 
-  if (profile_->GetPrefs()->GetBoolean(prefs::kBlockThirdPartyCookies)) {
+  if (profile_->GetPrefs()->GetBoolean(prefs::kBlockThirdPartyCookies) &&
+      origin != ORIGIN_OFFLINE) {
     RecordFinalStatusWithoutCreatingPrerenderContents(
         url, origin, FINAL_STATUS_BLOCK_THIRD_PARTY_COOKIES);
     return nullptr;
@@ -1174,6 +1186,11 @@ bool PrerenderManager::DoesRateLimitAllowPrerender(Origin origin) const {
   base::TimeDelta elapsed_time =
       GetCurrentTimeTicks() - last_prerender_start_time_;
   histograms_->RecordTimeBetweenPrerenderRequests(origin, elapsed_time);
+  // TODO(gabadie,pasko): Re-implement missing tests for
+  // FINAL_STATUS_RATE_LIMIT_EXCEEDED that where removed by:
+  //    http://crrev.com/a2439eeab37f7cb7a118493fb55ec0cb07f93b49.
+  if (origin == ORIGIN_OFFLINE)
+    return true;
   if (!config_.rate_limit_enabled)
     return true;
   return elapsed_time >=
@@ -1316,10 +1333,18 @@ NetworkPredictionStatus PrerenderManager::GetPredictionStatusForOrigin(
     Origin origin) const {
   DCHECK(CalledOnValidThread());
 
-  // LINK rel=prerender origins ignore the network state and the privacy
-  // settings.
+  // <link rel=prerender> origins ignore the network state and the privacy
+  // settings. Web developers should be able prefetch with all possible privacy
+  // settings and with all possible network types. This would avoid web devs
+  // coming up with creative ways to prefetch in cases they are not allowed to
+  // do so.
+  //
+  // Offline originated prerenders also ignore the network state and privacy
+  // settings because they are controlled by the offliner logic via
+  // PrerenderHandle.
   if (origin == ORIGIN_LINK_REL_PRERENDER_SAMEDOMAIN ||
-      origin == ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN) {
+      origin == ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN ||
+      origin == ORIGIN_OFFLINE) {
     return NetworkPredictionStatus::ENABLED;
   }