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..9c86399cb577949889bed1405a2e8c68edd37ecc 100644
--- a/blimp/engine/common/blimp_browser_context.cc
+++ b/blimp/engine/common/blimp_browser_context.cc
@@ -7,14 +7,27 @@
 #include "base/bind.h"
 #include "base/environment.h"
 #include "base/files/file_util.h"
+#include "base/memory/ptr_util.h"
 #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 {
+// Function for optionally handling read errors. Is a no-op for Blimp.
+// While the PersistentPrefStore's interface is supported, it is an in-memory
+// store only.
+void IgnoreReadError(PersistentPrefStore::PrefReadError error) {}
+}  // namespace
+
 namespace blimp {
 namespace engine {
 
@@ -59,6 +72,10 @@ BlimpBrowserContext::BlimpBrowserContext(bool off_the_record,
       off_the_record_(off_the_record),
       net_log_(net_log) {
   InitWhileIOAllowed();
+  InitPrefService();
+  metrics_service_client_.reset(
+      new BlimpMetricsServiceClient(pref_service_.get(),
+                                    GetSystemRequestContextGetter()));
 }
 
 BlimpBrowserContext::~BlimpBrowserContext() {
@@ -79,6 +96,23 @@ void BlimpBrowserContext::InitWhileIOAllowed() {
   BrowserContext::Initialize(this, path_);
 }
 
+void BlimpBrowserContext::InitPrefService() {
+  // Create PrefRegistry and register metrics services preferences with it.
+  scoped_refptr<user_prefs::PrefRegistrySyncable> pref_registry(
+      new user_prefs::PrefRegistrySyncable());
+  metrics::MetricsService::RegisterPrefs(pref_registry.get());
+  PrefServiceFactory pref_service_factory;
+
+  // Create an in memory preferences store to hold metrics logs.
+  pref_service_factory.set_user_prefs(new InMemoryPrefStore());
+  pref_service_factory.set_read_error_callback(base::Bind(&IgnoreReadError));
+
+  // Create a PrefService binding the PrefRegistry to the InMemoryPrefStore.
+  // The PrefService ends up owning the PrefRegistry and the InMemoryPrefStore.
+  pref_service_ = pref_service_factory.Create(pref_registry.get());
+  DCHECK(pref_service_.get());
+}
+
 std::unique_ptr<content::ZoomLevelDelegate>
 BlimpBrowserContext::CreateZoomLevelDelegate(const base::FilePath&) {
   return nullptr;