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

This patch adds out of line copy constructors for classes that our
clang-plugin considers heavy. This is an effort to enable copy
constructor checks by default.

BUG=436357
[email protected], [email protected], [email protected]
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1728033002

Cr-Commit-Position: refs/heads/master@{#377717}
diff --git a/components/drive/file_change.h b/components/drive/file_change.h
index 9d885b8..40d750c 100644
--- a/components/drive/file_change.h
+++ b/components/drive/file_change.h
@@ -59,6 +59,7 @@
     typedef std::deque<Change> List;
 
     ChangeList();
+    ChangeList(const ChangeList& other);
     ~ChangeList();
 
     // Updates the list with the |new_change|.