Reland Refactor FakeAttachmentStore

Reland Refactor FakeAttachmentStore

Refactor FakeAttachmentStore into AttachmentStoreProxy and
InMemoryAttachmentStore backend. Break AttachmentStore interface into
AttachmentStoreBase (common interface for backends) and AttachmentStore
(referenced by datatype and AttachmentService).

BUG=
R=maniscalco@chromium.org

Committed: https://crrev.com/c4c7e842b3ba77671b74ac263e5fb7217c3dfbfb
Cr-Commit-Position: refs/heads/master@{#297951}

[pavely, 2014-10-01 00:14:38]

Patchset #2 (id:20001) has been deleted

[pavely, 2014-10-01 00:51:49]

I fixed memory leaks. Patchset 1 is original change, patchset 2 is fix.
PTAL

https://codereview.chromium.org/616983002/diff/40001/sync/internal_api/attach...
File sync/internal_api/attachments/attachment_store_handle.cc (right):

https://codereview.chromium.org/616983002/diff/40001/sync/internal_api/attach...
sync/internal_api/attachments/attachment_store_handle.cc:57: void
AttachmentStoreHandle::ResetBackend() {
I had to extract this code into separate function and call from derived class
because in there DeleteSoon should happen before RunLoop.

[pavely, 2014-10-01 17:54:47]

Patchset #2 (id:40001) has been deleted

[pavely, 2014-10-01 18:12:11]

Patchset #2 (id:60001) has been deleted

[pavely, 2014-10-01 18:39:57]

PTAL. This is the fix we discussed this morning.

[pavely, 2014-10-02 21:45:28]

PTAL.

[maniscalco, 2014-10-02 21:53:31]

On 2014/10/02 21:45:28, pavely wrote:
> PTAL.

LGTM (assuming it passes linux_chromium_asan_rel).

[pavely, 2014-10-02 22:33:58]

The CQ bit was checked by pavely@chromium.org

[commit-bot: I haz the power, 2014-10-02 22:35:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/616983002/100001

[commit-bot: I haz the power, 2014-10-02 23:43:09]

Committed patchset #3 (id:100001) as 604f95a61a23783a8df2d23038333e1f6031b590

[commit-bot: I haz the power, 2014-10-02 23:45:35]

Patchset 3 (id:??) landed as
https://crrev.com/c4c7e842b3ba77671b74ac263e5fb7217c3dfbfb
Cr-Commit-Position: refs/heads/master@{#297951}