Fix widget visibility accounting when crashing in background.

Fix widget visibility accounting when crashing in background.

RenderWidgetHostImpl tracks its visibility using the |is_hidden_| field.
This value should be not be reset when the renderer crashes, otherwise a
widget that crashes in backround will think it's already visible when
put in foreground, messing up process visibility accounting.

This patch fixes process visibility for processes that crashed in
background and are respawned upon foregrounding by preserving the
|is_hidden_| field through renderer crashes.

BUG=399521
R=aelias@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287864

[ppi, 2014-08-06 14:29:50]

Hi Alexandre, ptal.

Not sure what'd be a proper low-level test for this, but an embedder-side
integration test is in review at
https://chrome-internal-review.googlesource.com/#/c/171261/ .

[ppi, 2014-08-06 16:54:02]

PS the line being removed was introduced in the initial chromium commit, so no
clue if it was intended to serve any concrete purpose

[aelias_OOO_until_Jul13, 2014-08-06 18:27:31]

lgtm

[ppi, 2014-08-06 18:33:47]

Thanks!

[ppi, 2014-08-06 18:33:57]

The CQ bit was checked by ppi@chromium.org

[commit-bot: I haz the power, 2014-08-06 18:37:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ppi@chromium.org/443133002/1

[ppi, 2014-08-06 21:30:20]

The CQ bit was unchecked by ppi@chromium.org

[ppi, 2014-08-06 21:30:54]

The CQ bit was checked by ppi@chromium.org

[commit-bot: I haz the power, 2014-08-06 21:33:54]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ppi@chromium.org/443133002/1

[ppi, 2014-08-06 21:38:35]

Committed patchset #1 manually as 287864 (presubmit successful).