Revert 255262 "Migrate chrome.bluetooth API backend to use devic..."

Revert 255262 "Migrate chrome.bluetooth API backend to use devic..."

Reverted due to memory leaks.

> 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

TBR=armansito@chromium.org
BUG=349942
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=255372

[earthdok, 2014-03-06 16:50:16]

Committed patchset #1 manually as r255372.