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

chrome/browser/instant/instant_controller.h

Index: chrome/browser/instant/instant_controller.h
diff --git a/chrome/browser/instant/instant_controller.h b/chrome/browser/instant/instant_controller.h
index 250c31a6c0d10fb64a05141f033f20517b98aff2..f7a59349bf328365c8b681ab9eba6d12ce820649 100644
--- a/chrome/browser/instant/instant_controller.h
+++ b/chrome/browser/instant/instant_controller.h
@@ -47,6 +47,9 @@ class InstantController {
   // The URL for the local omnibox popup.
   static const char* kLocalOmniboxPopupURL;
 
+  // The key used to store search terms data in the NavigationEntry.
+  static const std::string kSearchTermsKey;
+
   // |use_local_preview_only| will force the use of kLocalOmniboxPopupURL as the
   // instant URL and is only applicable if |extended_enabled| is true.
   InstantController(chrome::BrowserInstantController* browser,
@@ -54,6 +57,8 @@ class InstantController {
                     bool use_local_preview_only);
   ~InstantController();
 
+  const string16& last_omnibox_text() const { return last_omnibox_text_; }
+
   // Invoked as the user types into the omnibox. |user_text| is what the user
   // has typed. |full_text| is what the omnibox is showing. These may differ if
   // the user typed only some text, and the rest was inline autocompleted. If
@@ -93,6 +98,9 @@ class InstantController {
   // Returns true if the Instant preview is showing a search results preview.
   bool IsPreviewingSearchResults() const;
 
+  // Returns true if an instant extended search is currently being done.
+  bool IsInstantExtendedSearch() const;
+
   // If the preview is showing search results, commits the preview, calling
   // CommitInstant() on the browser, and returns true. Else, returns false.
   bool CommitIfPossible(InstantCommitType type);