Enable TCP preconnect and DNS preresolve on cellular.

chrome/browser/net/prediction_options.cc

Index: chrome/browser/net/prediction_options.cc
diff --git a/chrome/browser/net/prediction_options.cc b/chrome/browser/net/prediction_options.cc
index 34fc98894e72e5c40f5ac2b8b2482c13378d0883..9666ccc4d36834816f39068a19ad65823185b547 100644
--- a/chrome/browser/net/prediction_options.cc
+++ b/chrome/browser/net/prediction_options.cc
@@ -34,6 +34,25 @@ bool CanPredictNetworkActions(int NetworkPredictionOptions,
   }
 }
 
+bool CanPreconnect(int NetworkPredictionOptions,
+                   bool NetworkPredictionEnabled) {

[mmenke, 2014/08/08 16:05:42]

These should be named network_prediction_options and network_prediction_enabled.
 Same goes for the above function.

[Bence, 2014/08/08 20:10:03]

Done.

+  switch (NetworkPredictionOptions) {
+    case chrome_browser_net::NETWORK_PREDICTION_ALWAYS:
+      return true;
+    // We allow TCP preconnect and DNS preresolution even on cellular networks
+    // if the user setting is WIFI_ONLY.

[mmenke, 2014/08/08 16:05:42]

nit:  Shouldn't use we in comments, since it's ambiguous (We the programmers, we
google, we meaning the program, etc).

[Bence, 2014/08/08 20:10:03]

Done.

+    case chrome_browser_net::NETWORK_PREDICTION_WIFI_ONLY:
+      return true;
+    case chrome_browser_net::NETWORK_PREDICTION_NEVER:
+      return false;
+    case chrome_browser_net::NETWORK_PREDICTION_UNSET:
+      return NetworkPredictionEnabled;
+    default:
+      NOTREACHED() << "Unknown kNetworkPredictionOptions value.";
+      return false;
+  }
+}
+
 }  // namespace
 
 namespace chrome_browser_net {
@@ -63,4 +82,20 @@ bool CanPredictNetworkActionsUI(PrefService* prefs) {
       prefs->GetBoolean(prefs::kNetworkPredictionEnabled));
 }
 
+bool CanPreconnectIO(ProfileIOData* profile_io_data) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  DCHECK(profile_io_data);
+

[mmenke, 2014/08/08 16:05:42]

optional nit:  The two IO thread functions have blank lines here, the two UI
thread ones do not.  I suggest being uniform about the decision, since the
functions are all so similar.  I'm fine either way.

[Bence, 2014/08/08 20:10:03]

Done.

+  return CanPreconnect(
+      profile_io_data->network_prediction_options()->GetValue(),
+      profile_io_data->network_prediction_enabled()->GetValue());
+}
+
+bool CanPreconnectUI(PrefService* prefs) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  DCHECK(prefs);
+  return CanPreconnect(prefs->GetInteger(prefs::kNetworkPredictionOptions),
+                       prefs->GetBoolean(prefs::kNetworkPredictionEnabled));
+}
+
 }  // namespace chrome_browser_net