autofill: Refactor PersonalDataManager::Observer into its own header file.

chrome/test/live_sync/autofill_helper.h

Index: chrome/test/live_sync/autofill_helper.h
diff --git a/chrome/test/live_sync/autofill_helper.h b/chrome/test/live_sync/autofill_helper.h
index 0c3dee49f3a31b98bde462f11d6a774efe2e7585..c97ae11245e7d864ece469d48b03235cc8ae3bcd 100644
--- a/chrome/test/live_sync/autofill_helper.h
+++ b/chrome/test/live_sync/autofill_helper.h
@@ -7,15 +7,18 @@
 #pragma once
 
 #include <set>
+#include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
-#include "chrome/browser/autofill/personal_data_manager.h"
+#include "base/string16.h"
 #include "chrome/test/live_sync/sync_datatype_helper.h"
 
 class AutofillEntry;
 class AutofillKey;
 class AutofillProfile;
+class AutofillType;
+class PersonalDataManager;
 class WebDataService;
 
 class AutofillHelper : public SyncDatatypeHelper {