Move AutofillWebData DB methods into separate class

components/autofill/browser/webdata/autofill_webdata_backend.h

+#ifndef COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_
+#define COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "components/autofill/browser/webdata/autofill_webdata.h"
+#include "components/autofill/common/form_field_data.h"
+#include "components/webdata/common/web_data_results.h"
+#include "components/webdata/common/web_data_service_base.h"
+#include "components/webdata/common/web_data_service_consumer.h"
+#include "components/webdata/common/web_database.h"
+
+namespace autofill {
+
+class AutofillChange;
+class AutofillProfile;
+class AutofillWebDataServiceObserverOnDBThread;
+class CreditCard;
+
+class AutofillWebDataBackend

[Ilya Sherman, 2013/04/30 00:14:08]

Please add documentation describing the purpose of this class.

[Cait (Slow), 2013/04/30 22:24:40]

Done.

+    : public base::RefCountedThreadSafe<AutofillWebDataBackend,
+          content::BrowserThread::DeleteOnDBThread> {

[Ilya Sherman, 2013/04/30 00:14:08]

Why is this class reference counted, rather than simply always accessed on the
DB thread?

[Cait (Slow), 2013/04/30 22:24:40]

It needs to be ref-counted as AutofillWebDataService posts tasks to it
asynchronously (from the UI thread).

[Ilya Sherman, 2013/04/30 23:52:11]

Seems like the AutofillWebDataService could just hold a WeakPtr to it; or if it
owns the lifetime, it could post asynchronous tasks to the DB thread to create
and destroy this object.

[Cait (Slow), 2013/05/01 23:14:19]

The async tasks have non-void return types (either the state of the DB, or the
data being requested), so a WeakPtr won't work here. 

The other option is to let AutofillWebDataService own the lifetime, any not
execute any DB requests that were made to AutofillWebDataService after
ShutdownOnUIThread() had been called (since the backend could disappear anytime
thereafter). Not sure if this would break any of the  clients or not though...

+ public:
+  AutofillWebDataBackend();
+
+  WebDatabase::State AddFormElementsImpl(

[Ilya Sherman, 2013/04/30 00:14:08]

nit: Could we drop the "Impl" suffix for all of these methods?

[Cait (Slow), 2013/04/30 22:24:40]

Done.

+      const std::vector<FormFieldData>& fields, WebDatabase* db);

[Ilya Sherman, 2013/04/30 00:14:08]

nit: Please leave a blank line after each method declaration, and please add
documentation for the methods.

[Ilya Sherman, 2013/04/30 00:14:08]

nit: If the entire method declaration doesn't fit on a single line, please wrap
things so that there is exactly one parameter per line.

[Cait (Slow), 2013/04/30 22:24:40]

Done.

[Cait (Slow), 2013/04/30 22:24:40]

Done.

+  scoped_ptr<WDTypedResult> GetFormValuesForElementNameImpl(
+      const base::string16& name, const base::string16& prefix, int limit,
+      WebDatabase* db);
+  WebDatabase::State RemoveFormElementsAddedBetweenImpl(
+      const base::Time& delete_begin, const base::Time& delete_end,
+      WebDatabase* db);
+  WebDatabase::State RemoveExpiredFormElementsImpl(WebDatabase* db);
+  WebDatabase::State RemoveFormValueForElementNameImpl(
+      const base::string16& name, const base::string16& value, WebDatabase* db);
+  WebDatabase::State AddAutofillProfileImpl(
+      const AutofillProfile& profile, WebDatabase* db);
+  WebDatabase::State UpdateAutofillProfileImpl(
+      const AutofillProfile& profile, WebDatabase* db);
+  WebDatabase::State RemoveAutofillProfileImpl(
+      const std::string& guid, WebDatabase* db);
+  scoped_ptr<WDTypedResult> GetAutofillProfilesImpl(WebDatabase* db);
+  WebDatabase::State AddCreditCardImpl(
+      const CreditCard& credit_card, WebDatabase* db);
+  WebDatabase::State UpdateCreditCardImpl(
+      const CreditCard& credit_card, WebDatabase* db);
+  WebDatabase::State RemoveCreditCardImpl(
+      const std::string& guid, WebDatabase* db);
+  scoped_ptr<WDTypedResult> GetCreditCardsImpl(WebDatabase* db);
+  WebDatabase::State RemoveAutofillDataModifiedBetweenImpl(
+      const base::Time& delete_begin, const base::Time& delete_end,
+      WebDatabase* db);
+
+  void AddObserver(AutofillWebDataServiceObserverOnDBThread* observer);
+  void RemoveObserver(AutofillWebDataServiceObserverOnDBThread* observer);
+
+ protected:
+  virtual ~AutofillWebDataBackend();
+
+ private:
+  friend struct content::BrowserThread::DeleteOnThread<
+      content::BrowserThread::DB>;
+  friend class base::DeleteHelper<AutofillWebDataBackend>;
+  // We have to friend RCTS<> so WIN shared-lib build is happy (crbug/112250).

[Ilya Sherman, 2013/04/30 00:14:08]

nit: Please prepend "http://" to the URL so that it is hyperlinked.

[Cait (Slow), 2013/04/30 22:24:40]

Done.

+  friend class base::RefCountedThreadSafe<AutofillWebDataBackend,
+      content::BrowserThread::DeleteOnDBThread>;
+
+  // Callbacks to ensure that sensitive info is destroyed if request is
+  // cancelled.
+  void DestroyAutofillProfileResult(const WDTypedResult* result);
+  void DestroyAutofillCreditCardResult(const WDTypedResult* result);
+
+  ObserverList<AutofillWebDataServiceObserverOnDBThread> db_observer_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutofillWebDataBackend);
+};
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_

[Ilya Sherman, 2013/04/30 00:14:08]

Any chance you could convince the source control tools that this file is
branched from autofill_webdata_service.h rather than it being a brand new file?

[Cait (Slow), 2013/04/30 22:24:40]

Done.