Add more out of line copy ctors for complex classes.

content/common/frame_replication_state.cc

Index: content/common/frame_replication_state.cc
diff --git a/content/common/frame_replication_state.cc b/content/common/frame_replication_state.cc
index 13cd626363a96d961637784ce73ae7015d1b1dcd..00e835f5b920cb619b19e8106391b63e8dc133bc 100644
--- a/content/common/frame_replication_state.cc
+++ b/content/common/frame_replication_state.cc
@@ -31,6 +31,9 @@ FrameReplicationState::FrameReplicationState(
       has_potentially_trustworthy_unique_origin(
           has_potentially_trustworthy_unique_origin) {}
 
+FrameReplicationState::FrameReplicationState(
+    const FrameReplicationState& other) = default;
+
 FrameReplicationState::~FrameReplicationState() {
 }