Camera: derive post RAW sensitivity keys for BC

Derive post RAW sensitivity keys for devices
earlier than HAL3.4.

Bug: 27950762
Change-Id: Icc2232cb722c61a5878a81706885303b15ddee3e
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index 96ca7b7..349fb4c 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -203,6 +203,10 @@
 
     uint32_t                   mDeviceVersion;
 
+    // whether Camera3Device should derive ANDROID_CONTROL_POST_RAW_SENSITIVITY_BOOST for
+    // backward compatibility. Should not be changed after initialization.
+    bool                       mDerivePostRawSensKey = false;
+
     struct Size {
         uint32_t width;
         uint32_t height;