bluetooth: android: Fix a couple of crashes when adapter is turned on/off.

device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.device.bluetooth;
 
 import android.Manifest;
 import android.annotation.TargetApi;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.le.ScanSettings;
@@ skipping 164 matching lines @@
         Wrappers.ContextWrapper context = mAdapter.getContext();
         return context.checkPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
                 || context.checkPermission(Manifest.permission.ACCESS_FINE_LOCATION);
     }
 
     /**
      * Starts a Low Energy scan.
      * @return True on success.
      */
     private boolean startScan() {
         Wrappers.BluetoothLeScannerWrapper scanner = mAdapter.getBluetoothLeScanner();

[scheib, 2016/01/21 05:33:51]

scanner may be null.

 
         if (!canScan()) {
             return false;
         }
 
         // scanMode note: SCAN_FAILED_FEATURE_UNSUPPORTED is caused (at least on some devices) if
         // setReportDelay() is used or if SCAN_MODE_LOW_LATENCY isn't used.
         int scanMode = ScanSettings.SCAN_MODE_LOW_LATENCY;
 
         assert mScanCallback == null;
         mScanCallback = new ScanCallback();
 
         try {
             scanner.startScan(null /* filters */, scanMode, mScanCallback);
         } catch (IllegalArgumentException e) {
             Log.e(TAG, "Cannot start scan: " + e);
             return false;
+        } catch (IllegalStateException e) {

[scheib, 2016/01/21 05:33:51]

Add a test:
- In Fakes.java have FakeBluetoothLeScanner's startScan() check a member
variable that indicates if an exception should be thrown. 
- Set that member variable from some new @CalledByNative method you add to
FakeBluetoothAdapter. 
- Call that method from the test fixture BluetoothTestAndroid, where you also
add a method so that tests can set this behavior.
- Different than existing patterns: because this is very Android implementation
specific, I think only add the method to BluetoothTestAndroid, not to
BluetoothTestBase.
- Add a test to bluetooth_adapter_unittest.cc in the general proximity of
'TEST_F(BluetoothTest, DiscoverySession)'. Comment is clearly as an Android
specific test. 

+            Log.e(TAG, "Adapter is off. Cannot start scan: " + e);
+            return false;
         }
         return true;
     }
 
     /**
      * Stops the Low Energy scan.
      * @return True if a scan was in progress.
      */
     private boolean stopScan() {
         if (mScanCallback == null) {
             return false;
         }
         try {
             mAdapter.getBluetoothLeScanner().stopScan(mScanCallback);
         } catch (IllegalArgumentException e) {
             Log.e(TAG, "Cannot stop scan: " + e);
             mScanCallback = null;
             return false;
+        } catch (IllegalStateException e) {
+            Log.e(TAG, "Adapter is off. Cannot stop scan: " + e);
+            mScanCallback = null;
+            return false;
         }
         mScanCallback = null;
         return true;
     }
 
     /**
      * Implements callbacks used during a Low Energy scan by notifying upon
      * devices discovered or detecting a scan failure.
      */
     private class ScanCallback extends Wrappers.ScanCallbackWrapper {
@@ skipping 27 matching lines @@
     // Binds to BluetoothAdapterAndroid::OnScanFailed.
     private native void nativeOnScanFailed(long nativeBluetoothAdapterAndroid);
 
     // Binds to BluetoothAdapterAndroid::CreateOrUpdateDeviceOnScan.
     // 'Object' type must be used for |bluetoothDeviceWrapper| because inner class
     // Wrappers.BluetoothDeviceWrapper reference is not handled by jni_generator.py JavaToJni.
     // http://crbug.com/505554
     private native void nativeCreateOrUpdateDeviceOnScan(long nativeBluetoothAdapterAndroid,
             String address, Object bluetoothDeviceWrapper, List<ParcelUuid> advertisedUuids);
 }