Create a PrefStore in support of Blimp metrics collection.

android_webview/browser/aw_browser_context.cc

Index: android_webview/browser/aw_browser_context.cc
diff --git a/android_webview/browser/aw_browser_context.cc b/android_webview/browser/aw_browser_context.cc
index 73d840c0f594771fbbeb1723780c9bf5709361b3..8732fde921217457b11b4cf55751a87d81933727 100644
--- a/android_webview/browser/aw_browser_context.cc
+++ b/android_webview/browser/aw_browser_context.cc
@@ -10,7 +10,6 @@
 #include "android_webview/browser/aw_form_database_service.h"
 #include "android_webview/browser/aw_metrics_service_client.h"
 #include "android_webview/browser/aw_permission_manager.h"
-#include "android_webview/browser/aw_pref_store.h"
 #include "android_webview/browser/aw_quota_manager_bridge.h"
 #include "android_webview/browser/aw_resource_context.h"
 #include "android_webview/browser/jni_dependency_factory.h"
@@ -32,6 +31,7 @@
 #include "components/policy/core/browser/configuration_policy_pref_store.h"
 #include "components/policy/core/browser/url_blacklist_manager.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 "components/url_formatter/url_fixer.h"
@@ -323,7 +323,8 @@ void AwBrowserContext::InitUserPrefService() {
   metrics::MetricsService::RegisterPrefs(pref_registry);
 
   PrefServiceFactory pref_service_factory;
-  pref_service_factory.set_user_prefs(make_scoped_refptr(new AwPrefStore()));
+  pref_service_factory.set_user_prefs(make_scoped_refptr(
+      new InMemoryPrefStore()));
   pref_service_factory.set_managed_prefs(
       make_scoped_refptr(new policy::ConfigurationPolicyPrefStore(
           browser_policy_connector_->GetPolicyService(),