bluetooth: android: Enable characteristic change notification events.

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

Index: device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
diff --git a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
index 81742c5914fc8863b816f2f487a4fb4d45413102..6b163d828a2969461823ec1590fbb9d4d8e4a630 100644
--- a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
+++ b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
@@ -186,6 +186,26 @@ final class ChromeBluetoothDevice {
         }
 
         @Override
+        public void onCharacteristicChanged(
+                final Wrappers.BluetoothGattCharacteristicWrapper characteristic) {
+            Log.i(TAG, "device onCharacteristicChanged.");
+            ThreadUtils.runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    ChromeBluetoothRemoteGattCharacteristic chromeCharacteristic =
+                            mWrapperToChromeCharacteristicsMap.get(characteristic);
+                    if (chromeCharacteristic == null) {
+                        // Android events arriving with no Chrome object is expected rarely only
+                        // when the event races object destruction.
+                        Log.v(TAG, "onCharacteristicChanged when chromeCharacteristic == null.");
+                    } else {
+                        chromeCharacteristic.onCharacteristicChanged();
+                    }
+                }
+            });
+        }
+
+        @Override
         public void onCharacteristicRead(
                 final Wrappers.BluetoothGattCharacteristicWrapper characteristic,
                 final int status) {