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

device/bluetooth/android/java/src/org/chromium/device/bluetooth/Wrappers.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.BluetoothDevice;
@@ skipping 28 matching lines @@
  *
  * Each Wrapper base class accepts an Android API object and passes through
  * calls to it. When under test, Fake subclasses override all methods that
  * pass through to the Android object and instead provide fake implementations.
  */
 @JNINamespace("device")
 @TargetApi(Build.VERSION_CODES.LOLLIPOP)
 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;
 
         /**
          * Creates a BluetoothAdapterWrapper using the default
@@ skipping 28 matching lines @@
             if (!hasLowEnergyFeature) {
                 Log.i(TAG, "BluetoothAdapterWrapper.create failed: No Low Energy support.");
                 return null;
             }
 
             BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
             if (adapter == null) {
                 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;
+                }
             }
         }
 
         public BluetoothAdapterWrapper(BluetoothAdapter adapter, ContextWrapper context,
                 BluetoothLeScannerWrapper scanner) {
             mAdapter = adapter;
             mContext = context;
             mScanner = scanner;
         }
 
@@ skipping 55 matching lines @@
         }
 
         public void startScan(
                 List<ScanFilter> filters, int scanSettingsScanMode, ScanCallbackWrapper callback) {
             ScanSettings settings =
                     new ScanSettings.Builder().setScanMode(scanSettingsScanMode).build();
 
             ForwardScanCallbackToWrapper callbackForwarder =
                     new ForwardScanCallbackToWrapper(callback);
             mCallbacks.put(callback, callbackForwarder);
-
             mScanner.startScan(filters, settings, callbackForwarder);
         }
 
         public void stopScan(ScanCallbackWrapper callback) {
             ForwardScanCallbackToWrapper callbackForwarder = mCallbacks.remove(callback);
             mScanner.stopScan(callbackForwarder);
         }
     }
 
     /**
@@ skipping 84 matching lines @@
                     mDevice.connectGatt(context, autoConnect,
                             new ForwardBluetoothGattCallbackToWrapper(callback, this)),
                     this);
         }
 
         public String getAddress() {
             return mDevice.getAddress();
         }
 
         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();
         }
 
         public int getBondState() {
             return mDevice.getBondState();
         }
 
         public String getName() {
             return mDevice.getName();
         }
@@ skipping 217 matching lines @@
 
         public byte[] getValue() {
             return mDescriptor.getValue();
         }
 
         public boolean setValue(byte[] value) {
             return mDescriptor.setValue(value);
         }
     }
 }