[mac] Implement a windowed extension install/permissions prompt.

This allows extension install dialogs, and permissions upgrade prompts,
to be shown on mac without requiring a parent WebContents to attach a
sheet to. Currently, they hit NOTIMPLEMENTED().

The window is a titled NSPanel, centred on screen using [NSWindow
center]. The implementation mostly uses the existing
ExtensionInstallViewController, but puts it in a new, windowed-version
of ExtensionInstallDialogController.

Adds a test:
WindowedInstallDialogControllerBrowserTest.ShowInstallDialog that mimics
the way extension install and upgrade prompts are invoked via the app
launcher.

Screenshot at http://crbug.com/325030#c2

BUG=325030, 229094, 271809, 269151

Review URL: https://codereview.chromium.org/65043015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238542 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238542
Roll openmax deps to r5205 to pick up x86 api compatibility fix.

This openmax_dl revision makes the FFT API the same for both ARM and X86 so that dependent code doesn't need to know. See https://webrtc-codereview.appspot.com/4749004/

BUG=
TBR=phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/102473002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238543 0039d316-1c4b-4281-b951-d872f2087c98
Fix scroll to section in the settings page.

BUG=321906

Review URL: https://codereview.chromium.org/102673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238544 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238545 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238545