[Search] Store and recall search terms using NavigationEntry to improve search term extraction

content/public/browser/navigation_entry.h

Index: content/public/browser/navigation_entry.h
diff --git a/content/public/browser/navigation_entry.h b/content/public/browser/navigation_entry.h
index cc25a254cf08c2904dc5aa10e5b09122a70f481f..f9dc8758f0f979f06cd5424ed17a6a02c3bcf4f0 100644
--- a/content/public/browser/navigation_entry.h
+++ b/content/public/browser/navigation_entry.h
@@ -188,6 +188,11 @@ class NavigationEntry {
   // is currently only used in tests.
   virtual void SetFrameToNavigate(const std::string& frame_name) = 0;
   virtual const std::string& GetFrameToNavigate() const = 0;
+
+  // Set extra data on this NavigationEntry.
+  virtual void SetExtraData(const std::string& key, const string16& data) = 0;
+  virtual const bool GetExtraData(const std::string& key, string16* data)
+      const = 0;
 };
 
 }  // namespace content