Ensure async selections after longpress activate the handles

Ensure async selections after longpress activate the handles

Fix an issue where the selection handles remain hidden if "empty"
selection updates occur after a longpress but before the nonempty
selection update.

BUG=393025
NOTRY=true

Committed: https://crrev.com/9a0d887094a3b66880edf8f48d0065b9ddf4c75e
Cr-Commit-Position: refs/heads/master@{#330190}

[jdduke (slow), 2015-05-15 18:49:03]

jdduke@chromium.org changed reviewers:
+ mohsen@chromium.org

[jdduke (slow), 2015-05-15 18:49:03]

mohsen@: PTAL, thanks. This is pretty bad, as any situation where the renderer
main thread is delayed can prevent the handles from showing after a longpress.

[mohsen, 2015-05-15 19:42:32]

LGTM, though this book keeping logic is getting a bit complicated and confusing.

[jdduke (slow), 2015-05-15 19:51:16]

On 2015/05/15 19:42:32, mohsen wrote:
> LGTM, though this book keeping logic is getting a bit complicated and
confusing.

Yeah, I had hoped this new bit would be simpler than resetting the cached
values... I'm not even sure if we really need the dirty bit any longer...

[jdduke (slow), 2015-05-15 19:51:56]

On 2015/05/15 19:51:16, jdduke wrote:
> On 2015/05/15 19:42:32, mohsen wrote:
> > LGTM, though this book keeping logic is getting a bit complicated and
> confusing.
> 
> Yeah, I had hoped this new bit would be simpler than resetting the cached
> values... I'm not even sure if we really need the dirty bit any longer...

Also, feel free to clean this up as you go along, a lot of this logic was
brought over from Android and it has evolved so much some of it may no longer be
necessary.

[jdduke (slow), 2015-05-15 19:52:03]

The CQ bit was checked by jdduke@chromium.org

[commit-bot: I haz the power, 2015-05-15 19:55:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139123009/1

[jdduke (slow), 2015-05-15 20:47:25]

The CQ bit was unchecked by jdduke@chromium.org

[jdduke (slow), 2015-05-15 20:47:53]

The CQ bit was checked by jdduke@chromium.org

[commit-bot: I haz the power, 2015-05-15 20:48:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139123009/1

[commit-bot: I haz the power, 2015-05-15 20:56:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-18 11:27:12]

Patchset 1 (id:??) landed as
https://crrev.com/9a0d887094a3b66880edf8f48d0065b9ddf4c75e
Cr-Commit-Position: refs/heads/master@{#330190}