Add signal handler for low disk notification

chromeos/dbus/fake_cryptohome_client.cc

Index: chromeos/dbus/fake_cryptohome_client.cc
diff --git a/chromeos/dbus/fake_cryptohome_client.cc b/chromeos/dbus/fake_cryptohome_client.cc
index 79064fb1ac75f84cff14f94019d3d015748e49ea..35ed5ebc30f2d11a87f6e35b14d55c71a52cf08d 100644
--- a/chromeos/dbus/fake_cryptohome_client.cc
+++ b/chromeos/dbus/fake_cryptohome_client.cc
@@ -52,6 +52,11 @@ void FakeCryptohomeClient::ResetAsyncCallStatusHandlers() {
   async_call_status_data_handler_.Reset();
 }
 
+void FakeCryptohomeClient::SetLowDiskSpaceHandler(
+    const LowDiskSpaceHandler& handler) {
+  low_disk_space_handler_ = handler;

[satorux1, 2016/06/28 00:48:29]

low_disk_space_handler_ is set but won't be used? Then I think we don't need
this member variable for now.

[dspaid, 2016/06/28 00:57:08]

Done.

+}
+
 void FakeCryptohomeClient::WaitForServiceToBeAvailable(
     const WaitForServiceToBeAvailableCallback& callback) {
   if (service_is_available_) {