Add InitWidgets() phase for GTK infobars.

Add InitWidgets() phase for GTK infobars.

This unifies the creation of GTK widgets and makes it happen in response to the infobar being shown. Currently, this generally happens at construction. Once the new ownership model lands, infobars will not yet be owned at construction time, and since widget creation includes getting a theme service from the owner, that needs to move out of the construction phase.

Incidentally, this also makes the GTK native object creation happen at the same time as the views native object creation, not that that matters much.

BUG=none
TEST=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=194707

[Peter Kasting, 2013-04-17 20:57:44]

Second attempt at https://codereview.chromium.org/11775019 .  The original patch
failed in debug mode (which my tryruns missed) because the GTK widgets were not
created during PlatformSpecificAddInfoBar(), but instead later during
PlatformSpecificShow().  This moves creation earlier.

The previously-reviewed patch is patch set 1, so only the diffs against that
need review.

[Elliot Glaysher, 2013-04-17 21:01:10]

On 2013/04/17 20:57:44, Peter Kasting wrote:
> Second attempt at https://codereview.chromium.org/11775019 .  The original
patch
> failed in debug mode (which my tryruns missed) because the GTK widgets were
not
> created during PlatformSpecificAddInfoBar(), but instead later during
> PlatformSpecificShow().  This moves creation earlier.
> 
> The previously-reviewed patch is patch set 1, so only the diffs against that
> need review.

lgtm. (It looks like the biggest chunk is just moving a function to the public
section and that the only functional change is moving from Show() to
AddInfoBar()).

[Peter Kasting, 2013-04-17 21:02:42]

On 2013/04/17 21:01:10, Elliot Glaysher wrote:
> lgtm. (It looks like the biggest chunk is just moving a function to the public
> section and that the only functional change is moving from Show() to
> AddInfoBar()).

That's correct.  I also added some comments elsewhere.

[Peter Kasting, 2013-04-17 23:02:40]

Committed patchset #2 manually as r194707 (presubmit successful).