Camera NDK: add user context set/get API

Also add ACaptureRequest_copy API.

Test: new NDK CTS test
Bug: 64266031
Change-Id: I77cee16621d92ff3a4cd0c929419a4972b2be040
diff --git a/camera/ndk/impl/ACaptureRequest.h b/camera/ndk/impl/ACaptureRequest.h
index e5b453e..06b2cc3 100644
--- a/camera/ndk/impl/ACaptureRequest.h
+++ b/camera/ndk/impl/ACaptureRequest.h
@@ -45,8 +45,19 @@
 };
 
 struct ACaptureRequest {
+    camera_status_t setContext(void* ctx) {
+        context = ctx;
+        return ACAMERA_OK;
+    }
+
+    camera_status_t getContext(void** ctx) const {
+        *ctx = context;
+        return ACAMERA_OK;
+    }
+
     ACameraMetadata*      settings;
     ACameraOutputTargets* targets;
+    void*                 context;
 };
 
 #endif // _ACAPTURE_REQUEST_H