Add Clone and disallow copy construction for NavigationEntryImpl.

content/browser/frame_host/navigation_entry_impl.h

Index: content/browser/frame_host/navigation_entry_impl.h
diff --git a/content/browser/frame_host/navigation_entry_impl.h b/content/browser/frame_host/navigation_entry_impl.h
index c69c978e0f416b60dab1fb6b7e9d9d307f56f8e9..f6d2a17f0ac222b141fe3270f6b10b6216021878 100644
--- a/content/browser/frame_host/navigation_entry_impl.h
+++ b/content/browser/frame_host/navigation_entry_impl.h
@@ -90,6 +90,15 @@ class CONTENT_EXPORT NavigationEntryImpl
   const std::vector<GURL>& GetRedirectChain() const override;
   bool IsRestored() const override;
 
+  // Creates a copy of this NavigationEntryImpl that can be modified
+  // independently from the original.  Does not copy any value that would be
+  // cleared in ResetForCommit.
+  // TODO(creis): Once we start sharing FrameNavigationEntries between
+  // NavigationEntryImpls, we will need to support two versions of Clone: one
+  // that shares the existing FrameNavigationEntries (for use within the same
+  // tab) and one that draws them from a different pool (for use in a new tab).

[Avi (use Gerrit), 2015/03/12 16:59:19]

Does this version of Clone have one of those behaviors? If you can decide what
those two Clones will be called
(CloneForSameController/CloneForDifferentController or maybe
CloneForController(NavController*) perhaps you might want to name it like that
now.

[Charlie Reis, 2015/03/12 17:07:43]

Yeah, I hadn't thought closely about whether to have two methods or give a
parameter, since I'm not sure what we'll need to pass in yet.  (So far
NavigationEntry doesn't depend on NavigationController at all, so it might be
nice to pass in some kind of mutable set of FrameNavigationEntries.)

At the moment, there's no difference between the behaviors since we don't have
shared entries.  Let's wait on the new name until there's a behavior difference.

+  NavigationEntryImpl* Clone() const;
+
   // Once a navigation entry is committed, we should no longer track several
   // pieces of non-persisted state, as documented on the members below.
   void ResetForCommit();
@@ -245,6 +254,7 @@ class CONTENT_EXPORT NavigationEntryImpl
   // later. If you add a new field that needs to be persisted you'll have to
   // update SessionService/TabRestoreService and Android WebView
   // state_serializer.cc appropriately.
+  // For all new fields, update |Clone| and possibly |ResetForCommit|.
   // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
 
   // The FrameNavigationEntry for the main frame.
@@ -369,7 +379,7 @@ class CONTENT_EXPORT NavigationEntryImpl
   // time (see TabNavigation for an example of this).
   std::map<std::string, base::string16> extra_data_;
 
-  // Copy and assignment is explicitly allowed for this class.
+  DISALLOW_COPY_AND_ASSIGN(NavigationEntryImpl);
 };
 
 }  // namespace content