bluetooth: android: Implement & test CreateGattConnection.

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 928d3baf654aacc92ecf66f3e9d4d6ec2579572a..8214515472bcca3d27e42e7fe0089998efbdf6bf 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
@@ -8,6 +8,8 @@ import android.Manifest;
 import android.annotation.TargetApi;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothGatt;
+import android.bluetooth.BluetoothGattCallback;
 import android.bluetooth.le.BluetoothLeScanner;
 import android.bluetooth.le.ScanCallback;
 import android.bluetooth.le.ScanFilter;
@@ -225,6 +227,12 @@ class Wrappers {
             mDevice = device;
         }
 
+        public BluetoothGattWrapper connectGatt(
+                Context context, boolean autoConnect, BluetoothGattCallbackWrapper callback) {
+            return new BluetoothGattWrapper(mDevice.connectGatt(
+                    context, autoConnect, new ForwardBluetoothGattCallbackToWrapper(callback)));
+        }
+
         public String getAddress() {
             return mDevice.getAddress();
         }
@@ -241,4 +249,52 @@ class Wrappers {
             return mDevice.getName();
         }
     }
+
+    /**
+     * Wraps android.bluetooth.BluetoothGatt.
+     */
+    static class BluetoothGattWrapper {
+        private final BluetoothGatt mGatt;
+
+        BluetoothGattWrapper(BluetoothGatt gatt) {
+            mGatt = gatt;
+        }
+
+        public void disconnect() {
+            mGatt.disconnect();
+        }
+    }
+
+    /**
+     * Implements android.bluetooth.BluetoothGattCallback and forwards calls through
+     * to a provided BluetoothGattCallbackWrapper instance.
+     *
+     * This class is required so that Fakes can use BluetoothGattCallbackWrapper
+     * without it extending from BluetoothGattCallback. Fakes must function even on
+     * Android versions where BluetoothGattCallback class is not defined.
+     */
+    static class ForwardBluetoothGattCallbackToWrapper extends BluetoothGattCallback {
+        final BluetoothGattCallbackWrapper mWrapperCallback;
+
+        ForwardBluetoothGattCallbackToWrapper(BluetoothGattCallbackWrapper wrapperCallback) {
+            mWrapperCallback = wrapperCallback;
+        }
+
+        @Override
+        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
+            mWrapperCallback.onConnectionStateChange(status, newState);
+        }
+    }
+
+    /**
+     * Wrapper alternative to android.bluetooth.BluetoothGattCallback allowing clients and Fakes to
+     * work on older SDK versions without having a dependency on the class not defined there.
+     *
+     * BluetoothGatt gatt parameters are omitted from methods as each call would
+     * need to wrap them in a BluetoothGattWrapper. Client code should cache the
+     * BluetoothGattWrapper provided on the initial BluetoothDeviceWrapper.connectGatt call.
+     */
+    abstract static class BluetoothGattCallbackWrapper {
+        public abstract void onConnectionStateChange(int status, int newState);
+    }
 }