Cleanup: Remove unused SearchTermsTracker

chrome/browser/search/search_terms_tracker.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROME_BROWSER_SEARCH_SEARCH_TERMS_TRACKER_H_
-#define CHROME_BROWSER_SEARCH_SEARCH_TERMS_TRACKER_H_
-
-#include <map>
-
-#include "base/macros.h"
-#include "base/strings/string16.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-
-namespace content {
-class NavigationController;
-class WebContents;
-}
-
-namespace chrome {
-
-// Observes navigation events (and WebContents destructions) to keep track of
-// search terms associated with a WebContents. Essentially, as long as there are
-// only web-triggerable navigations following a search results page, this class
-// will consider the search terms from that SRP as the "current" search terms.
-// Any other type of navigation will invalidate the search terms. The search
-// terms are being tracked so they can be displayed in the location bar for
-// related navigations that occur after a search.
-class SearchTermsTracker : public content::NotificationObserver {
- public:
-  SearchTermsTracker();
-  ~SearchTermsTracker() override;
-
-  // Returns the current search terms and navigation index of the corresponding
-  // search results page for the specified WebContents. This function will
-  // return true if there are valid search terms for |contents|. |search_terms|
-  // and/or |navigation_index| can be NULL if not needed.
-  bool GetSearchTerms(const content::WebContents* contents,
-                      base::string16* search_terms,
-                      int* navigation_index) const;
-
-  // content::NotificationObserver
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
- private:
-  struct TabData {
-    TabData() : srp_navigation_index(-1) {}
-    base::string16 search_terms;
-    int srp_navigation_index;
-  };
-
-  // Keeps information about the specified WebContents.
-  typedef std::map<const content::WebContents*, TabData> TabState;
-
-  // Searches for the most recent search and, if found, fills |tab_data| with
-  // information about that search and returns true.
-  bool FindMostRecentSearch(const content::NavigationController* controller,
-                            TabData* tab_data);
-
-  // Removes the TabData entry associated to the specified |contents|.
-  void RemoveTabData(const content::WebContents* contents);
-
-  content::NotificationRegistrar registrar_;
-  TabState tabs_;
-
-  DISALLOW_COPY_AND_ASSIGN(SearchTermsTracker);
-};
-
-}  // namespace chrome
-
-#endif  // CHROME_BROWSER_SEARCH_SEARCH_TERMS_TRACKER_H_