Fixes several focus issue with extension browser action popups

Fixes several focus issue with popup in the extensions' browser actions:
- when opening a browser action popup, it gets the focus.
- tab traversal now works in the popup
- pressing esc closes the popup (if the keyboard event is not processed by the page)

BUG=22654, 28087, 28086
TEST=Create an extension with a browser extension that shows a popup. Make the popup
     so that it has a textfield (that gets focused when the popup show) and a button.
     Install the extension. Open the popup, the textfield should have focus. Press
     tab, the focus should go to the button. Press Esc, the popup should be closed.


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=32335

[Erik does not do reviews, 2009-11-18 01:59:35]

LGTM - just nits

http://codereview.chromium.org/402036/diff/9/1015
File chrome/browser/extensions/extension_host.cc (right):

http://codereview.chromium.org/402036/diff/9/1015#newcode485
Line 485: #endif
add TODO(port)

http://codereview.chromium.org/402036/diff/9/1019
File chrome/browser/views/browser_actions_container.cc (right):

http://codereview.chromium.org/402036/diff/9/1019#newcode457
Line 457: // Forward the focus to the renderer.
nit: newline above comment

http://codereview.chromium.org/402036/diff/9/1017
File chrome/browser/views/extensions/extension_view.cc (right):

http://codereview.chromium.org/402036/diff/9/1017#newcode25
Line 25: // This view needs to be focusable so it can act as the focused view
for the
nit: newline above comment.

http://codereview.chromium.org/402036/diff/9/1017#newcode181
Line 181: 
nit: remove newline