Merge 260900 "linux_aura: Port GtkKeybindingsHandler to Aura."

Merge 260900 "linux_aura: Port GtkKeybindingsHandler to Aura."

> linux_aura: Port GtkKeybindingsHandler to Aura.
> 
> This is a quick hack to move the current GtkKeybindingsHandler code into
> aura builds. This is necessary so that Linux users who have set custom
> keybindings can use them in edit fields. This only works in the content
> area; further patches are needed for this to work in views.
> 
> This redoes the interface so that instead of being hard coded into
> content, we have a general interface set in ui/wm/. This should allow
> views to also use this code in ui/views/, as well as its current usage
> in content/.
> 
> BUG=319437, 358297
> R=piman@chromium.org, sadrul@chromium.org, sky@chromium.org
> 
> Review URL: https://codereview.chromium.org/213283004

TBR=erg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=263304

[msw, 2014-04-11 19:03:43]

Committed patchset #1 manually as r263304.