Fix threading issues in aw form database

Fix threading issues in aw form database

BUG=285584
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=221892

[sgurun-gerrit only, 2013-09-04 23:59:54]

PTAL, thanks.

[joth, 2013-09-05 00:59:10]

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_br...
File android_webview/browser/aw_browser_context.cc (right):

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_br...
android_webview/browser/aw_browser_context.cc:153: new
AwFormDatabaseService(context_storage_path_));
just call this "new AwFormDatabaseService" from AwBrowserContext c'tor

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_fo...
File android_webview/browser/aw_form_database_service.cc (right):

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_fo...
android_webview/browser/aw_form_database_service.cc:69: base::AutoLock
lock(lock_);
I don't understand what problem this lock is solving

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_fo...
android_webview/browser/aw_form_database_service.cc:87: // TODO(sgurun)
investigate if it is better to do on DB thread
I can answer this: it's *definitely* better done on DB thread. 
1/ in general, bouncing a synchronous call to UI thread risks a deadlock if the
caller is (naughtily) blocking UI thread waiting for a result from the
background thread using this API
2/ as written, the code here will 100% deadlock if called from UI thread.

[sgurun-gerrit only, 2013-09-05 02:58:45]

removed locks as we speak.

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_br...
File android_webview/browser/aw_browser_context.cc (right):

https://codereview.chromium.org/23803005/diff/1/android_webview/browser/aw_br...
android_webview/browser/aw_browser_context.cc:153: new
AwFormDatabaseService(context_storage_path_));
On 2013/09/05 00:59:10, joth wrote:
> just call this "new AwFormDatabaseService" from AwBrowserContext c'tor

Done.

[joth, 2013-09-05 03:03:44]

lgtm with nits

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
File android_webview/browser/aw_form_database_service.cc (right):

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
android_webview/browser/aw_form_database_service.cc:51: // of pending queries.
DCHECK(result_map_.empty()) ?

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
android_webview/browser/aw_form_database_service.cc:120:
it->second.completion->Signal();
result_map_.erase(it)

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
File android_webview/browser/aw_form_database_service.h (right):

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
android_webview/browser/aw_form_database_service.h:48: struct PendingQuery {
some people would use std::pair<> but I think this is more readable :)

[sgurun-gerrit only, 2013-09-05 03:17:17]

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
File android_webview/browser/aw_form_database_service.cc (right):

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
android_webview/browser/aw_form_database_service.cc:51: // of pending queries.
On 2013/09/05 03:03:44, joth wrote:
> DCHECK(result_map_.empty()) ?

Done.

https://codereview.chromium.org/23803005/diff/7001/android_webview/browser/aw...
android_webview/browser/aw_form_database_service.cc:120:
it->second.completion->Signal();
On 2013/09/05 03:03:44, joth wrote:
> result_map_.erase(it)

Done.

[commit-bot: I haz the power, 2013-09-05 03:17:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sgurun@chromium.org/23803005/12001

[commit-bot: I haz the power, 2013-09-05 03:55:07]

Retried try job too often on ios_dbg_simulator for step(s) ui_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=ios_dbg_si...

[commit-bot: I haz the power, 2013-09-05 06:47:06]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sgurun@chromium.org/23803005/12001

[commit-bot: I haz the power, 2013-09-05 07:15:38]

Retried try job too often on ios_dbg_simulator for step(s) ui_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=ios_dbg_si...

[sgurun-gerrit only, 2013-09-06 23:32:24]

PTAL, thx

[joth, 2013-09-07 00:41:41]

On 2013/09/06 23:32:24, sgurun wrote:
> PTAL, thx

lgtm

[commit-bot: I haz the power, 2013-09-07 00:42:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sgurun@chromium.org/23803005/39001

[commit-bot: I haz the power, 2013-09-07 04:39:30]

Change committed as 221892