[incremental] use vold to mount/unmount IncrementalFileSystem

Let vold mount IncFs onto directories under data and open control files.

Test: builds
Change-Id: Ibd96aae254b4fefaf56c9d549c4672a987c46221
diff --git a/VoldNativeService.h b/VoldNativeService.h
index 13137c5..0718263 100644
--- a/VoldNativeService.h
+++ b/VoldNativeService.h
@@ -141,6 +141,13 @@
     binder::Status supportsBlockCheckpoint(bool* _aidl_return);
     binder::Status supportsFileCheckpoint(bool* _aidl_return);
     binder::Status resetCheckpoint();
+
+    binder::Status incFsVersion(int32_t* _aidl_return) override;
+    binder::Status mountIncFs(
+            const std::string& imagePath, const std::string& targetDir, int32_t flags,
+            ::android::os::incremental::IncrementalFileSystemControlParcel* _aidl_return) override;
+    binder::Status unmountIncFs(const std::string& dir) override;
+    binder::Status bindMount(const std::string& sourceDir, const std::string& targetDir) override;
 };
 
 }  // namespace vold