Fixing crash in StartFinding (2nd attempt)....

chrome/browser/views/find_bar_view.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/views/find_bar_view.h"
 
 #include <algorithm>
 
 #include "base/string_util.h"
 #include "chrome/browser/tab_contents/web_contents.h"
@@ skipping 150 matching lines @@
     // Background images for the Find edit box.
     kBackground = rb.GetBitmapNamed(IDR_FIND_BOX_BACKGROUND);
     if (UILayoutIsRightToLeft())
       kBackground_left = rb.GetBitmapNamed(IDR_FIND_BOX_BACKGROUND_LEFT_RTL);
     else
       kBackground_left = rb.GetBitmapNamed(IDR_FIND_BOX_BACKGROUND_LEFT);
   }
 }
 
 FindBarView::~FindBarView() {
-  // We are going away so we don't want to be notified about further updates
-  // to the text field. Otherwise, it can lead to crashes, as exposed by
-  // automation testing in issue 8048.
-  find_text_->SetController(NULL);
 }
 
 void FindBarView::SetFindText(const std::wstring& find_text) {
   find_text_->SetText(find_text);
 }
 
 void FindBarView::UpdateForResult(const FindNotificationDetails& result,
                                   const std::wstring& find_text) {
   bool have_valid_range =
       result.number_of_matches() != -1 && result.active_match_ordinal() != -1;
@@ skipping 252 matching lines @@
       NOTREACHED() << L"Unknown button";
       break;
   }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // FindBarView, views::TextField::Controller implementation:
 
 void FindBarView::ContentsChanged(views::TextField* sender,
                                   const std::wstring& new_contents) {
+  // We must guard against a NULL web_contents, which can happen if the text
+  // in the Find box is changed right after the tab is destroyed. Otherwise, it
+  // can lead to crashes, as exposed by automation testing in issue 8048.
+  if (!container_->web_contents())
+    return;
+
   // When the user changes something in the text box we check the contents and
   // if the textbox contains something we set it as the new search string and
   // initiate search (even though old searches might be in progress).
   if (new_contents.length() > 0) {
     container_->web_contents()->StartFinding(new_contents, true);
   } else {
     // The textbox is empty so we reset.
     container_->web_contents()->StopFinding(true);  // true = clear selection on
                                                     // page.
     UpdateForResult(container_->web_contents()->find_result(),
@@ skipping 29 matching lines @@
 }
 
 bool FindBarView::FocusForwarderView::OnMousePressed(
     const views::MouseEvent& event) {
   if (view_to_focus_on_mousedown_) {
     view_to_focus_on_mousedown_->ClearSelection();
     view_to_focus_on_mousedown_->RequestFocus();
   }
   return true;
 }