Add incognito:split to Chrome Connectivity Diagnostics app

BUG=346862

Review URL: https://codereview.chromium.org/181063036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255261 0039d316-1c4b-4281-b951-d872f2087c98
Migrate chrome.bluetooth API backend to use device::BluetoothDiscoverySession.

Modified chrome.bluetooth API code to use the new discovery session API for
device discovery.

BUG=346982
TEST=1. unit_tests, browser_tests
     2. Use multiple running extension instances with the bluetooth permission and check for the following behavior:
        - Only one session per extension. Calling chrome.bluetooth.stopDiscovery from one running app should fail if that app never called chrome.bluetooth.startDiscovery.
        - An app's discovery sessions should get cleaned up if that app crashes or unloads.
        - Use bt_console and run "power off". This should cause all discovery sessions that have been assigned to apps to get marked as inactive. Verify by requesting a new discovery session from apps, which should succeed.

Review URL: https://codereview.chromium.org/179123008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255262 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255261
SVN changes up to revision 255262
Bring back -fstack-protector-all on iOS.

This flag used to cause a crash on startup. As of Xcode 5 this doesn't
appear to happen anymore.

BUG=341484
TEST=None

Review URL: https://codereview.chromium.org/187823005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255263 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255263