Adding support for pre-sent messages

components/copresence/public/copresence_constants.h

Index: components/copresence/public/copresence_constants.h
diff --git a/components/copresence/public/copresence_constants.h b/components/copresence/public/copresence_constants.h
index ae75f77d8f5597e7e0c24d10a4a2430e5d2d4571..8efa2d8f522969b548e82d2b5785ba76ab516421 100644
--- a/components/copresence/public/copresence_constants.h
+++ b/components/copresence/public/copresence_constants.h
@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_CONSTANTS_H_
 #define COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_CONSTANTS_H_
 
+#include <google/protobuf/repeated_field.h>
+
 #include <string>
 #include <vector>
 
@@ -20,6 +22,7 @@ class AudioBusRefCounted;
 namespace copresence {
 
 class Directive;
+class SubscribedMessage;
 
 // Audio constants. Currently used from the AudioPlayer/AudioRecorder.
 // TODO(rkc): Make these values configurable then remove them from here.
@@ -72,6 +75,10 @@ using SamplesCallback =
 // Callback to pass a list of directives back to CopresenceState.
 using DirectivesCallback = base::Callback<void(const std::vector<Directive>&)>;
 
+// Callback to pass around a list of SubscribedMessages.
+using MessagesCallback = base::Callback<void(
+    const google::protobuf::RepeatedPtrField<SubscribedMessage>&)>;
+
 }  // namespace copresence
 
 #endif  // COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_CONSTANTS_H_