Add default template initialization.

Adds a flow for Metadata to initialize templates.
PartialMetadataInterfaces expose another populate method,
which use a default value getter from ControlOptionsInterfaces.

BUG: 30140438
TEST: unit tests pass

Change-Id: I1c01469dcf4d06f7c4c62ebe2acd3d9b2294a161
diff --git a/modules/camera/3_4/metadata/metadata.h b/modules/camera/3_4/metadata/metadata.h
index 0683df2..e2232b5 100644
--- a/modules/camera/3_4/metadata/metadata.h
+++ b/modules/camera/3_4/metadata/metadata.h
@@ -33,6 +33,8 @@
 
   int FillStaticMetadata(android::CameraMetadata* metadata);
   bool IsValidRequest(const android::CameraMetadata& metadata);
+  int GetRequestTemplate(int template_type,
+                         android::CameraMetadata* template_metadata);
   int SetRequestSettings(const android::CameraMetadata& metadata);
   int FillResultMetadata(android::CameraMetadata* metadata);