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 d53e233a287494ab8e05cb6583106e8b51f2bd6e..9bcb3f8f3b04b2b31f92d0e5819b62d5ced034fc 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
@@ -46,6 +46,8 @@ import java.util.UUID;
 class Wrappers {
     private static final String TAG = "Bluetooth";
 
+    public static final int DEVICE_CLASS_UNSPECIFIED = 0x1F00;
+
     /**
      * Wraps android.bluetooth.BluetoothAdapter.
      */
@@ -94,8 +96,13 @@ 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()));
+                BluetoothLeScanner scanner = adapter.getBluetoothLeScanner();

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

In my patch you'll see that I moved the code for obtaining the scanner to the
point where it is attempted to be used. I did this because there was a scenario
where it is null the first time - I hadn't carefully tracked it down, but it
would seem logical to be:
- Close all browser activities (recents, swipe off all)
- Turn off Bluetooth.
- Launch browser and initiate Bluetooth scan.
- Enable Bluetooth.
- Return to web page and retry scan.

Similar to how I suggest adding a test for scan exceptions, please add a test
for the adapter being present but powered off before the first scan, then
powering on, then scanning. In this case I think it is reasonable for all
platforms, so please add methods all the way to BluetoothTestBase.

Also a test for being powered on, then off, then scanning.

Fake adapter's 'getBluetoothLeScanner' should return null based on the adapter
powered state.

+                if (scanner != null) {
+                    return new BluetoothAdapterWrapper(adapter, new ContextWrapper(context),
+                            new BluetoothLeScannerWrapper(scanner));
+                } else {
+                    return null;
+                }
             }
         }
 
@@ -171,7 +178,6 @@ class Wrappers {
             ForwardScanCallbackToWrapper callbackForwarder =
                     new ForwardScanCallbackToWrapper(callback);
             mCallbacks.put(callback, callbackForwarder);
-
             mScanner.startScan(filters, settings, callbackForwarder);
         }
 
@@ -276,6 +282,11 @@ class Wrappers {
         }
 
         public int getBluetoothClass_getDeviceClass() {
+            if (mDevice == null || mDevice.getBluetoothClass() == null) {

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

OK, no test needed here because we don't Fake getBluetoothClass and always
return unspecified anyway. 

+                // 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();
         }