Implement prediction_options.

chrome/browser/net/prediction_helper.cc

Index: chrome/browser/net/prediction_helper.cc
diff --git a/chrome/browser/net/prediction_helper.cc b/chrome/browser/net/prediction_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..10143d0ea7b927876d3ae6d6ed415a6976e96fe0
--- /dev/null
+++ b/chrome/browser/net/prediction_helper.cc
@@ -0,0 +1,67 @@
+// Copyright 2014 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/net/prediction_helper.h"
+
+#include "base/prefs/pref_service.h"
+#include "chrome/browser/net/predictor.h"
+#include "chrome/browser/profiles/profile_io_data.h"
+#include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "net/base/network_change_notifier.h"
+
+namespace {
+
+bool CanPredictNetworkActions(int AllowNetworkPrediction,
+                              bool NetworkPredictionEnabled) {
+  switch (AllowNetworkPrediction) {
+    case chrome_browser_net::Predictor::NETWORK_PREDICTION_ALWAYS:
+      return true;
+    case chrome_browser_net::Predictor::NETWORK_PREDICTION_WIFI_ONLY:
+      return !net::NetworkChangeNotifier::IsConnectionCellular(
+                 net::NetworkChangeNotifier::GetConnectionType());

[mmenke, 2014/06/26 20:41:01]

nit:  Suggest just using a 4-space indent here.

[Bence, 2014/06/27 15:11:50]

Done.

+    case chrome_browser_net::Predictor::NETWORK_PREDICTION_NEVER:
+      return false;
+    case chrome_browser_net::Predictor::NETWORK_PREDICTION_UNSET:
+      return NetworkPredictionEnabled;
+    default:
+      NOTREACHED() << "Unknown kAllowNetworkPrediction value.";

[mmenke, 2014/06/26 20:41:01]

Include base/logging.h for NOTREACHED and DCHECK.

[Bence, 2014/06/27 15:11:50]

Done.

+      return false;
+  }
+}
+
+}  // anonymous namespace

[mmenke, 2014/06/26 20:41:01]

nit:  --anonymous

[Bence, 2014/06/27 15:11:50]

Done.

+
+namespace chrome_browser_net {
+
+void RegisterPredictionHelperProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterIntegerPref(
+      prefs::kAllowNetworkPrediction,
+      chrome_browser_net::Predictor::NETWORK_PREDICTION_UNSET,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
+}
+
+// To be executed on the IO thread only.

[mmenke, 2014/06/26 20:41:01]

Function level comments should generally be with their declaration, rather than
their definition.  In this case, the comment is redundant with what you have in
the header file, so should just get rid of it.

[Bence, 2014/06/27 15:11:50]

Done.

+bool CanPredictNetworkActionsIO(content::ResourceContext* resource_context) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  DCHECK(resource_context);

[mmenke, 2014/06/26 20:41:01]

nit:  Generally, there's a blank line between DCHECKs and other code, if the
function is long enough.  Makes it easier to review.

[Bence, 2014/06/27 15:11:50]

Done.

+  ProfileIOData* io_data = ProfileIOData::FromResourceContext(resource_context);
+  if (io_data == NULL)

[mmenke, 2014/06/26 20:41:01]

Can this ever be NULL?  Looks like other consumers of this function don't do
this check.  In general, the Chrome philosophy is not to handle things that can
never happen, unless they could result in a security bug.  In this case, we'd
get crash dumps.

[Bence, 2014/06/27 15:11:50]

Done.

+    return false;
+  return CanPredictNetworkActions(
+      io_data->allow_network_prediction()->GetValue(),
+      io_data->network_prediction_enabled()->GetValue());
+}
+
+// To be executed on the UI thread only.

[mmenke, 2014/06/26 20:41:01]

nit:  Remove comment.

[Bence, 2014/06/27 15:11:50]

Done.

+bool CanPredictNetworkActionsUI(PrefService* prefs) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  DCHECK(prefs);
+  return CanPredictNetworkActions(
+      prefs->GetInteger(prefs::kAllowNetworkPrediction),
+      prefs->GetBoolean(prefs::kNetworkPredictionEnabled));
+}
+
+}  // namespace chrome_browser_net