chrome: Add out-of-line copy ctors for complex classes.

chrome/utility/media_galleries/ipc_data_source.cc

Index: chrome/utility/media_galleries/ipc_data_source.cc
diff --git a/chrome/utility/media_galleries/ipc_data_source.cc b/chrome/utility/media_galleries/ipc_data_source.cc
index fb7ffa5bcb4b37ec4b2ea0410d01f244ebe97f02..6d99fe95ccb27d34048c247a9fb23e91be8db714 100644
--- a/chrome/utility/media_galleries/ipc_data_source.cc
+++ b/chrome/utility/media_galleries/ipc_data_source.cc
@@ -66,6 +66,8 @@ IPCDataSource::Request::Request()
     : destination(NULL) {
 }
 
+IPCDataSource::Request::Request(const Request& other) = default;
+
 IPCDataSource::Request::~Request() {
 }