Disable Uber navigation for Settings & Help overlays

When accessing chrome://settings/overlayName or chrome://help/channel-change-page,
uber.onContentFrameLoaded is mistakenly called *after* the overlay is opened. This function
always brings the navigation frame to the foreground, so it should be called before any overlay
might be opened. The overlay being opened will then cause the navigation frame to recede
into the background.

This was inadvertently broken in r287989 (issue 423533003).

BUG=401903
TBR=dbeam@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288394

[michaelpg, 2014-08-08 14:03:42]

The CQ bit was checked by michaelpg@chromium.org

[michaelpg, 2014-08-08 14:03:47]

https://codereview.chromium.org/452113002/diff/20001/chrome/browser/resources...
File chrome/browser/resources/help/help.js (right):

https://codereview.chromium.org/452113002/diff/20001/chrome/browser/resources...
chrome/browser/resources/help/help.js:25: uber.onContentFrameLoaded();
I wouldn't mind updating help_browsertest.js to test this as well, but the
channel change overlay doesn't always exist (so the navigation frame won't be
disabled). Specifically, it should exist if:
m
1. we are on Linux and #defined(OS_CHROME), or
2. we are on a CrOS device and #defined(OS_CHROME) and
#defined(GOOGLE_CHROME_BUILD)

I can make a C++ test fixture to make base::SysInfo::IsRunningOnChromeOS()
available to the JS here, but want to check first if there's a simple way to do
this check.

[commit-bot: I haz the power, 2014-08-08 14:05:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/michaelpg@chromium.org/452113002/20001

[commit-bot: I haz the power, 2014-08-08 15:29:12]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/44373)
  win8_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_rel...)
  win_chromium_compile_dbg on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)
  win_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel/...)
  win_chromium_x64_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[Dan Beam, 2014-08-08 18:11:28]

lgtm

[commit-bot: I haz the power, 2014-08-08 18:18:50]

Change committed as 288394