Create and integrate a metrics service client into Blimp engine.

blimp/engine/common/blimp_browser_context.cc

Index: blimp/engine/common/blimp_browser_context.cc
diff --git a/blimp/engine/common/blimp_browser_context.cc b/blimp/engine/common/blimp_browser_context.cc
index 6a2a7ec04ad9ba83d257b766bf9ef850515804b0..0c591fc521dd6975612a21086992248c37a0aebd 100644
--- a/blimp/engine/common/blimp_browser_context.cc
+++ b/blimp/engine/common/blimp_browser_context.cc
@@ -10,11 +10,22 @@
 #include "base/nix/xdg_util.h"
 #include "base/path_service.h"
 #include "blimp/engine/app/blimp_permission_manager.h"
+#include "components/metrics/metrics_service.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/in_memory_pref_store.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/pref_service_factory.h"
 #include "content/public/browser/background_sync_controller.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/common/content_switches.h"
 
+namespace {
+// Shows notifications which correspond to PersistentPrefStore's reading errors.
+void HandleReadError(PersistentPrefStore::PrefReadError error) {
+}
+}  // namespace
+
 namespace blimp {
 namespace engine {
 
@@ -68,6 +79,17 @@ BlimpBrowserContext::~BlimpBrowserContext() {
   }
 }
 
+void BlimpBrowserContext::Initialize() {
+  InitPrefService();
+  BlimpMetricsServiceClient::GetInstance()->Initialize(
+      pref_service_.get(),
+      GetSystemRequestContextGetter());
+}
+
+void BlimpBrowserContext::Finalize() {
+  BlimpMetricsServiceClient::GetInstance()->Finalize();
+}
+
 void BlimpBrowserContext::InitWhileIOAllowed() {
   // Ensures ~/.config/blimp_engine directory exists.
   std::unique_ptr<base::Environment> env(base::Environment::Create());
@@ -79,6 +101,17 @@ void BlimpBrowserContext::InitWhileIOAllowed() {
   BrowserContext::Initialize(this, path_);
 }
 
+void BlimpBrowserContext::InitPrefService() {
+  user_prefs::PrefRegistrySyncable* pref_registry =

[Alexei Svitkine (slow), 2016/04/25 20:44:25]

Nit: unique_ptr

[Jess, 2016/04/26 00:01:25]

Unique ptr is not usable in this case since user_prefs::PrefRegistrySyncable has
a private destructor.  Using scoped_refptr instead.

+      new user_prefs::PrefRegistrySyncable();
+  metrics::MetricsService::RegisterPrefs(pref_registry);
+  PrefServiceFactory pref_service_factory;
+  // The pref storage for metrics logs.
+  pref_service_factory.set_user_prefs(new InMemoryPrefStore());
+  pref_service_factory.set_read_error_callback(base::Bind(&HandleReadError));
+  pref_service_ = pref_service_factory.Create(pref_registry);
+}
+
 std::unique_ptr<content::ZoomLevelDelegate>
 BlimpBrowserContext::CreateZoomLevelDelegate(const base::FilePath&) {
   return nullptr;