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

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

Index: device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.java
diff --git a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.java b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.java
index 8f14d298e1065d973325c7870de22253f3660b20..242f5efda02f6e13ec1ed86f82052ae8ecb4cdef 100644
--- a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.java
+++ b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.java
@@ -46,13 +46,15 @@ import java.util.UUID;
 class Wrappers {
     private static final String TAG = "Bluetooth";
 
+    public static final int DEVICE_CLASS_UNSPECIFIED = 0x1F00;
+
     /**
      * Wraps android.bluetooth.BluetoothAdapter.
      */
     static class BluetoothAdapterWrapper {
         private final BluetoothAdapter mAdapter;
         protected final ContextWrapper mContext;
-        protected final BluetoothLeScannerWrapper mScanner;
+        protected BluetoothLeScannerWrapper mScannerWrapper;
 
         /**
          * Creates a BluetoothAdapterWrapper using the default
@@ -94,32 +96,32 @@ class Wrappers {
                 Log.i(TAG, "BluetoothAdapterWrapper.create failed: Default adapter not found.");
                 return null;
             } else {
-                return new BluetoothAdapterWrapper(adapter, new ContextWrapper(context),
-                        new BluetoothLeScannerWrapper(adapter.getBluetoothLeScanner()));
+                return new BluetoothAdapterWrapper(adapter, new ContextWrapper(context));
             }
         }
 
-        public BluetoothAdapterWrapper(BluetoothAdapter adapter, ContextWrapper context,
-                BluetoothLeScannerWrapper scanner) {
+        public BluetoothAdapterWrapper(BluetoothAdapter adapter, ContextWrapper context) {
             mAdapter = adapter;
             mContext = context;
-            mScanner = scanner;
         }
 
-        public ContextWrapper getContext() {
-            return mContext;
+        public String getAddress() {
+            return mAdapter.getAddress();
         }
 
         public BluetoothLeScannerWrapper getBluetoothLeScanner() {
-            return mScanner;
-        }
-
-        public boolean isEnabled() {
-            return mAdapter.isEnabled();
+            BluetoothLeScanner scanner = mAdapter.getBluetoothLeScanner();
+            if (scanner == null) {
+                return null;
+            }
+            if (mScannerWrapper == null) {
+                mScannerWrapper = new BluetoothLeScannerWrapper(scanner);
+            }
+            return mScannerWrapper;
         }
 
-        public String getAddress() {
-            return mAdapter.getAddress();
+        public ContextWrapper getContext() {
+            return mContext;
         }
 
         public String getName() {
@@ -133,6 +135,18 @@ class Wrappers {
         public boolean isDiscovering() {
             return mAdapter.isDiscovering();
         }
+
+        public boolean isEnabled() {
+            return mAdapter.isEnabled();
+        }
+
+        public boolean setPowered(boolean powered) {

[scheib, 2016/02/05 18:06:19]

The wrapper should mimic the Android API as closely as possible, such that one
could replace the wrapper instance in the code that uses it with the system
Adapter type and have it compile and work. Please expose wrapper methods for
enable/disable instead of 'setPowered'. 

[perja, 2016/02/08 14:48:31]

Done.

+            if (powered) {
+                return mAdapter.enable();
+            } else {
+                return mAdapter.disable();
+            }
+        }
     }
 
     /**
@@ -155,7 +169,7 @@ class Wrappers {
      * Wraps android.bluetooth.BluetoothLeScanner.
      */
     static class BluetoothLeScannerWrapper {
-        private final BluetoothLeScanner mScanner;
+        protected final BluetoothLeScanner mScanner;
         private final HashMap<ScanCallbackWrapper, ForwardScanCallbackToWrapper> mCallbacks;
 
         public BluetoothLeScannerWrapper(BluetoothLeScanner scanner) {
@@ -171,7 +185,6 @@ class Wrappers {
             ForwardScanCallbackToWrapper callbackForwarder =
                     new ForwardScanCallbackToWrapper(callback);
             mCallbacks.put(callback, callbackForwarder);
-
             mScanner.startScan(filters, settings, callbackForwarder);

[scheib, 2016/02/05 18:06:19]

Leave the blank line.

[perja, 2016/02/08 14:48:31]

Done.

         }
 
@@ -276,6 +289,11 @@ class Wrappers {
         }
 
         public int getBluetoothClass_getDeviceClass() {
+            if (mDevice == null || mDevice.getBluetoothClass() == null) {
+                // BluetoothDevice.getBluetoothClass() returns null if adapter has been powered off.
+                // Return DEVICE_CLASS_UNSPECIFIED in these cases.
+                return DEVICE_CLASS_UNSPECIFIED;
+            }
             return mDevice.getBluetoothClass().getDeviceClass();
         }