Fix a race condition in preference metric reporting.

chrome/browser/profiles/profile_impl.cc

Index: chrome/browser/profiles/profile_impl.cc
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index d8c3ce3b0f6ba2bd86d8af156bd7c31c13556694..41dea64da3ce6f781a64b43d6920d7a1d6a0209d 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -60,6 +60,7 @@
 #include "chrome/browser/policy/profile_policy_connector_factory.h"
 #include "chrome/browser/prefs/browser_prefs.h"
 #include "chrome/browser/prefs/chrome_pref_service_factory.h"
+#include "chrome/browser/prefs/pref_hash_store_impl.h"
 #include "chrome/browser/prefs/pref_service_syncable.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/bookmark_model_loaded_observer.h"
@@ -93,6 +94,7 @@
 #include "content/public/browser/storage_partition.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_constants.h"
+#include "grit/browser_resources.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -118,6 +120,9 @@
 #if defined(OS_WIN)
 #include "chrome/browser/profiles/file_path_verifier_win.h"
 #include "chrome/installer/util/install_util.h"
+#if defined(ENABLE_RLZ)
+#include "rlz/lib/machine_id.h"
+#endif
 #endif
 
 #if defined(OS_CHROMEOS)
@@ -257,6 +262,33 @@ void SchedulePrefsFileVerification(const base::FilePath& prefs_file) {
 #endif
 }
 
+scoped_ptr<PrefHashStore> GetPrefHashStore(Profile* profile) {
+  // TODO(erikwright): Enable this on Android when race condition is sorted out.
+#if defined(OS_ANDROID)
+  return scoped_ptr<PrefHashStore>();
+#else
+  std::string seed = ResourceBundle::GetSharedInstance().GetRawDataResource(
+      IDR_PREF_HASH_SEED_BIN).as_string();
+  std::string device_id;
+
+#if defined(OS_WIN) && defined(ENABLE_RLZ)
+  // This is used by
+  // chrome/browser/extensions/api/music_manager_private/device_id_win.cc
+  // but that API is private (http://crbug.com/276485) and other platforms are
+  // not available synchronously.
+  // As part of improving pref metrics on other platforms we may want to find
+  // ways to defer preference loading until the device ID can be used.
+  rlz_lib::GetMachineId(&device_id);
+#endif
+
+  return scoped_ptr<PrefHashStore>(new PrefHashStoreImpl(
+      profile->GetPath().AsUTF8Unsafe(),
+      seed,
+      device_id,
+      g_browser_process->local_state()));
+#endif
+}
+
 }  // namespace
 
 // static
@@ -460,6 +492,7 @@ ProfileImpl::ProfileImpl(
         sequenced_task_runner,
         profile_policy_connector_->policy_service(),
         managed_user_settings,
+        GetPrefHashStore(this),
         new ExtensionPrefStore(
             ExtensionPrefValueMapFactory::GetForBrowserContext(this), false),
         pref_registry_,