Fix find-in-page "1 of 0" bug.

content/browser/find_request_manager.cc

 // Copyright 2016 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.
 
 #include "content/browser/find_request_manager.h"
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/common/input_messages.h"
@@ skipping 140 matching lines @@
   // Check for an update to the number of matches.
   if (number_of_matches != -1) {
     DCHECK_GE(number_of_matches, 0);
     auto matches_per_frame_it = matches_per_frame_.find(rfh);
     if (int matches_delta = number_of_matches - matches_per_frame_it->second) {
       // Increment the global number of matches by the number of additional
       // matches found for this frame.
       number_of_matches_ += matches_delta;
       matches_per_frame_it->second = number_of_matches;
 
+      // All matches may have been removed since the last find reply.
+      if (rfh == active_frame_ && !number_of_matches)
+        relative_active_match_ordinal_ = 0;
+
       // The active match ordinal may need updating since the number of matches
       // before the active match may have changed.
-      if (rfh != active_frame_)
+      if (rfh != active_frame_ || !number_of_matches)
         UpdateActiveMatchOrdinal();
     }
   }
 
   // Check for an update to the selection rect.
   if (!selection_rect.IsEmpty())
     selection_rect_ = selection_rect;
 
   // Check for an update to the active match ordinal.
   if (active_match_ordinal > 0) {
@@ skipping 462 matching lines @@
             aggregate_rects.end(), frame_rects.begin(), frame_rects.end());
       }
     }
     contents_->NotifyFindMatchRectsReply(
         match_rects_.known_version, aggregate_rects, match_rects_.active_rect);
   }
 }
 #endif
 
 }  // namespace content