Add DeviceSettingProvider unit tests.

chrome/browser/metrics/metrics_service.cc

Index: chrome/browser/metrics/metrics_service.cc
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index b11a44b1fad332fce1948d47ea3854adb8b0073d..745c6c95369255bae10aca1ef756ede2fa23de2e 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -402,6 +402,20 @@ MetricsService::MetricsService()
   log_manager_.set_max_ongoing_log_store_size(kUploadLogAvoidRetransmitSize);
 }
 
+// Constrcutor for tests. Will not initialize the object for realz.
+MetricsService::MetricsService(bool active)
+    : recording_active_(active),
+      reporting_active_(active),
+      state_(INITIALIZED),
+      io_thread_(NULL),
+      idle_since_last_transmission_(false),
+      next_window_id_(0),
+      ALLOW_THIS_IN_INITIALIZER_LIST(self_ptr_factory_(this)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(state_saver_factory_(this)),
+      waiting_for_asynchronus_reporting_step_(false) {
+  DCHECK(IsSingleThreaded());
+}
+
 MetricsService::~MetricsService() {
   SetRecording(false);
 }