Update prerender policy for custom tabs

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 4bb07b23169a97432e1a9cb06d1239f8751ae0d1..5f1d631a70f8d193c2e20f5b606abdd085cf259e 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -297,9 +297,11 @@ PrerenderHandle* PrerenderManager::AddPrerenderFromExternalRequest(
     const GURL& url,
     const content::Referrer& referrer,
     SessionStorageNamespace* session_storage_namespace,
-    const gfx::Size& size) {
-  return AddPrerender(ORIGIN_EXTERNAL_REQUEST, url, referrer, size,
-                      session_storage_namespace);
+    const gfx::Size& size,
+    bool prerender_on_mobile) {
+  Origin origin = prerender_on_mobile ? ORIGIN_EXTERNAL_REQUEST_MOBILE
+      : ORIGIN_EXTERNAL_REQUEST;
+  return AddPrerender(origin, url, referrer, size, session_storage_namespace);
 }
 
 PrerenderHandle* PrerenderManager::AddPrerenderForInstant(
@@ -934,7 +936,8 @@ PrerenderHandle* PrerenderManager::AddPrerender(
   // histogram tracking.
   histograms_->RecordPrerender(origin, url_arg);
 
-  NetworkPredictionStatus prerendering_status = GetPredictionStatus();
+  NetworkPredictionStatus prerendering_status =
+      GetPredictionStatusForOrigin(origin);
   if (prerendering_status != NetworkPredictionStatus::ENABLED) {
     FinalStatus final_status =
         prerendering_status == NetworkPredictionStatus::DISABLED_DUE_TO_NETWORK
@@ -1285,6 +1288,16 @@ NetworkPredictionStatus PrerenderManager::GetPredictionStatus() const {
   return CanPrefetchAndPrerenderUI(profile_->GetPrefs());
 }
 
+NetworkPredictionStatus PrerenderManager::GetPredictionStatusForOrigin(
+    Origin origin) const {
+  NetworkPredictionStatus prerender_status = GetPredictionStatus();

[pasko, 2016/03/10 14:21:37]

nit: s/prerender_status/prediction_status/

[Yusuf, 2016/03/10 18:55:53]

Done.

+  if (prerender_status == NetworkPredictionStatus::DISABLED_DUE_TO_NETWORK
+      && origin == ORIGIN_EXTERNAL_REQUEST_MOBILE) {
+    prerender_status = NetworkPredictionStatus::ENABLED;
+  }
+  return prerender_status;
+}
+
 void PrerenderManager::AddProfileNetworkBytesIfEnabled(int64_t bytes) {
   DCHECK_GE(bytes, 0);
   if (GetPredictionStatus() == NetworkPredictionStatus::ENABLED &&