Bluetooth: unregister the agent on CancelPairing()

BluetoothOptionsHandler will call BluetoothDevice::CancelPairing()
when it's being torn down, after which pointers to it (e.g. the
pairing_delegate_ pointer) are invalid.

Thus unregister the agent at this point rather than waiting for a
response from the backend.

BUG=none
TEST=verify no crash when clicking Cancel or Reject during pairing

Review URL: https://chromiumcodereview.appspot.com/14273036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@197085 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 1 deletions

diff --git a/device/bluetooth/bluetooth_device_experimental_chromeos.cc b/device/bluetooth/bluetooth_device_experimental_chromeos.cc
index 09c1ddf..d3ef05e 100644
--- a/device/bluetooth/bluetooth_device_experimental_chromeos.cc
+++ b/device/bluetooth/bluetooth_device_experimental_chromeos.cc
@@ -226,6 +226,10 @@ void BluetoothDeviceExperimentalChromeOS::CancelPairing() {
             base::Bind(
                 &BluetoothDeviceExperimentalChromeOS::OnCancelPairingError,
                 weak_ptr_factory_.GetWeakPtr()));
+
+    // Since there's no calback to this method, it's possible that the pairing
+    // delegate is going to be freed before things complete.
+    UnregisterAgent();
   }
 }
 
@@ -556,7 +560,9 @@ void BluetoothDeviceExperimentalChromeOS::OnSetTrusted(bool success) {
 }
 
 void BluetoothDeviceExperimentalChromeOS::UnregisterAgent() {
-  DCHECK(agent_.get());
+  if (!agent_.get())
+    return;
+
   DCHECK(pairing_delegate_);
 
   DCHECK(pincode_callback_.is_null());