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

components/nacl/browser/pnacl_host.h

Index: components/nacl/browser/pnacl_host.h
diff --git a/components/nacl/browser/pnacl_host.h b/components/nacl/browser/pnacl_host.h
index bacd71e6e32af1f71cee94e6583b35fb5b07c768..c3da05c47ea90f060978d85e4997c8efe66abf3c 100644
--- a/components/nacl/browser/pnacl_host.h
+++ b/components/nacl/browser/pnacl_host.h
@@ -116,6 +116,7 @@ class PnaclHost {
   class PendingTranslation {
    public:
     PendingTranslation();
+    PendingTranslation(const PendingTranslation& other);
     ~PendingTranslation();
     base::ProcessHandle process_handle;
     int render_view_id;