Implement Android key/value backup

chrome/browser/chrome_browser_main_android.cc

Index: chrome/browser/chrome_browser_main_android.cc
diff --git a/chrome/browser/chrome_browser_main_android.cc b/chrome/browser/chrome_browser_main_android.cc
index dbb1287b135041a08702e99bcad0a6df5b2e89fe..09c22d2df347fd2e079eecf42e6c9e2b96906a0d 100644
--- a/chrome/browser/chrome_browser_main_android.cc
+++ b/chrome/browser/chrome_browser_main_android.cc
@@ -87,6 +87,9 @@ void ChromeBrowserMainPartsAndroid::PostProfileInit() {
       content::BrowserThread::FILE, FROM_HERE,
       base::Bind(&DeleteFileTask, bookmark_image_file_path),
       base::TimeDelta::FromMinutes(1));
+  // Start watching the preferences that need to be backed up backup using
+  // Android backup, so that we create a new backup if they change.
+  backup_watcher_.reset(new chrome::android::ChromeBackupWatcher(profile()));
 }
 
 void ChromeBrowserMainPartsAndroid::PreEarlyInitialization() {