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 93 matching lines @@
     private boolean isPresent() {
         return mAdapter != null;
     }
 
     // Implements BluetoothAdapterAndroid::IsPowered.
     @CalledByNative
     private boolean isPowered() {
         return isPresent() && mAdapter.isEnabled();
     }
 
+    // Implements BluetoothAdapterAndroid::SetPowered.
+    @CalledByNative
+    private boolean setPowered(boolean powered) {
+        if (powered) {
+            return isPresent() && mAdapter.enable();
+        } else {
+            return isPresent() && mAdapter.disable();
+        }
+    }
+
     // Implements BluetoothAdapterAndroid::IsDiscoverable.
     @CalledByNative
     private boolean isDiscoverable() {
         return isPresent()
                 && mAdapter.getScanMode() == BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
     }
 
     // Implements BluetoothAdapterAndroid::IsDiscovering.
     @CalledByNative
     private boolean isDiscovering() {
@@ skipping 53 matching lines @@
                 || context.checkPermission(Manifest.permission.ACCESS_FINE_LOCATION);
     }
 
     /**
      * Starts a Low Energy scan.
      * @return True on success.
      */
     private boolean startScan() {
         Wrappers.BluetoothLeScannerWrapper scanner = mAdapter.getBluetoothLeScanner();
 
+        if (scanner == null) {
+            return false;
+        }
+
         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);
+            mScanCallback = null;
+            return false;
+        } catch (IllegalStateException e) {
+            Log.e(TAG, "Adapter is off. Cannot start scan: " + e);
+            mScanCallback = null;
             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);
+            Wrappers.BluetoothLeScannerWrapper scanner = mAdapter.getBluetoothLeScanner();
+            if (scanner != null) {
+                scanner.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 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);
 }