[GTK] Fix for muted tooltips while sound is playing.

[GTK] Fix for muted tooltips while sound is playing.

Tab media indicator data model updates indirectly cause TabGtk::UpdateTooltipState() to be invoked several times per second.  This in turned resulted in calling gtk_widget_set_tooltip_text() redundantly.  GTK responds to any tooltip text setter calls by hiding *all* tooltips throughout the application.

The fix is to check whether the tooltip text actually is different, and not call the setter when the text is unchanged.

In the bigger picture, there are other times when normal browser functionality would cause UpdateTooltipState() to be called several times per second.  In general, the current implementation for handling tab data model updates is expensive and in bad need of rewriting.  However, efforts would be better spent on moving Linux Chrome over to Aura.

BUG=333002
TEST=Confirmed fixed using bug repro steps.
R=erg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=245103

[miu, 2014-01-15 23:15:08]

erg: PTAL.  This is intended to be a patch for M32 (yes, stable!) and M33.

[Elliot Glaysher, 2014-01-15 23:17:42]

Ugly terrible no good hack LGTM!

[miu, 2014-01-15 23:21:31]

On 2014/01/15 23:17:42, Elliot Glaysher wrote:
> Ugly terrible no good hack LGTM!

Heheh...Yeah, I won't lie.  It's definitely an ugly hack.  Getting Linux Chrome
moved over to Aura is my excuse, and I stand by it!  ;-)

Thanks for the quick turnaround.

[commit-bot: I haz the power, 2014-01-15 23:53:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/miu@chromium.org/138413006/1

[miu, 2014-01-16 04:00:29]

Committed patchset #1 manually as r245103 (presubmit successful).