Support reading multiple InterfaceProviderSpecs from manifests

services/service_manager/public/cpp/interface_provider_spec.h

Index: services/service_manager/public/cpp/interface_provider_spec.h
diff --git a/services/service_manager/public/cpp/interface_provider_spec.h b/services/service_manager/public/cpp/interface_provider_spec.h
index 2e430aa66c28ab4f9421544eaeafb865a182f0a4..5b8591164075e733f1eef928794e5295c467072e 100644
--- a/services/service_manager/public/cpp/interface_provider_spec.h
+++ b/services/service_manager/public/cpp/interface_provider_spec.h
@@ -8,6 +8,7 @@
 #include <map>
 #include <set>
 #include <string>
+#include <unordered_map>
 
 namespace service_manager {
 
@@ -30,6 +31,10 @@ struct InterfaceProviderSpec {
   std::map<Name, CapabilitySet> requires;
 };
 
+// Map of spec name -> spec.
+using InterfaceProviderSpecMap =
+    std::unordered_map<std::string, InterfaceProviderSpec>;
+
 }  // namespace service_manager
 
 #endif  // SERVICES_SERVICE_MANAGER_PUBLIC_CPP_INTERFACE_PROVIDER_SPEC_H_