Persist Directory to disk when the app is backgrounded.

chrome/browser/sync/profile_sync_service_android.cc

Index: chrome/browser/sync/profile_sync_service_android.cc
diff --git a/chrome/browser/sync/profile_sync_service_android.cc b/chrome/browser/sync/profile_sync_service_android.cc
index 567297cc9c73ec7f3cee65a6117d4c43ed2b2733..b0c97e0d7e95fc73e57022aa6db8b4e656798865 100644
--- a/chrome/browser/sync/profile_sync_service_android.cc
+++ b/chrome/browser/sync/profile_sync_service_android.cc
@@ -181,6 +181,12 @@ void ProfileSyncServiceAndroid::SignOutSync(JNIEnv* env, jobject) {
   sync_prefs_->SetStartSuppressed(false);
 }
 
+void ProfileSyncServiceAndroid::FlushDirectory(JNIEnv* env, jobject) {
+  if (sync_service_ != nullptr) {

[nyquist, 2014/09/10 17:43:09]

Use NULL instead of nullptr.

Also, DCHECK for UI thread?

And thirdly, is it common for this to be null? If not, there is already a DCHECK
in the constructor for this. Since this is not static, I would assume that the
service would always be there?

[maxbogue, 2014/09/10 20:11:02]

Added the DCHECK. I've removed the null check entirely; I think I only added it
trying to fix the crash that the other null check prevented.

+    sync_service_->FlushDirectory();
+  }
+}
+
 ScopedJavaLocalRef<jstring> ProfileSyncServiceAndroid::QuerySyncStatusSummary(
     JNIEnv* env, jobject) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));