Camera: Add support for torch strength control.

This change consists of support to control flashunit brightness level
and getting the current brightness level for the flash unit associated
with camera device.

Test: Flashlight CTS
Bug: 200174275
Change-Id: I7f0b4c826e6ccef157ec22a3b3b8cf75a6b2152d
diff --git a/camera/tests/CameraBinderTests.cpp b/camera/tests/CameraBinderTests.cpp
index 9f2f430..17ea512 100644
--- a/camera/tests/CameraBinderTests.cpp
+++ b/camera/tests/CameraBinderTests.cpp
@@ -96,6 +96,12 @@
         return binder::Status::ok();
     };
 
+    virtual binder::Status onTorchStrengthLevelChanged(const String16& /*cameraId*/,
+            int32_t /*torchStrength*/) {
+        // No op
+        return binder::Status::ok();
+    }
+
     virtual binder::Status onCameraAccessPrioritiesChanged() {
         // No op
         return binder::Status::ok();