Check for null CONTROL_AWB_LOCK_AVAILABLE value in VideoCamera2

Check that the value for this property is not null before trying
to use its value.

Bug: 1031921
Change-Id: I164ad850775df07fa5b993d7db51e671fc5bfa36
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2185491
Auto-Submit: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
Reviewed-by: Marina Ciocea <marinaciocea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#766351}

media/capture/video/android/java/src/org/chromium/media/VideoCaptureCamera2.java

@@ -624,7 +624,9 @@ public class VideoCaptureCamera2 extends VideoCapture {
                 }
             }
             try {
-                if (cameraCharacteristics.get(CameraCharacteristics.CONTROL_AWB_LOCK_AVAILABLE)) {
+                Boolean awb_lock_available =
+                        cameraCharacteristics.get(CameraCharacteristics.CONTROL_AWB_LOCK_AVAILABLE);
+                if (awb_lock_available != null && awb_lock_available.booleanValue()) {
                     whiteBalanceModes.add(Integer.valueOf(AndroidMeteringMode.FIXED));
                 }
             } catch (NoSuchFieldError e) {