Display a tooltip when mouse hovers over a folder in the bookmark bar.

chrome/browser/ui/views/bookmarks/bookmark_bar_view.cc

 // Copyright (c) 2011 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/ui/views/bookmarks/bookmark_bar_view.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <vector>
@@ skipping 128 matching lines @@
     show_animation_.reset(new ui::SlideAnimation(this));
     if (BookmarkBarView::testing_) {
       // For some reason during testing the events generated by animating
       // throw off the test. So, don't animate while testing.
       show_animation_->Reset(1);
     } else {
       show_animation_->Show();
     }
   }
 
-  bool GetTooltipText(const gfx::Point& p, std::wstring* tooltip) {
+  virtual bool GetTooltipText(const gfx::Point& p,
+                              std::wstring* tooltip) OVERRIDE {
     gfx::Point location(p);
     ConvertPointToScreen(this, &location);
     *tooltip = BookmarkBarView::CreateToolTipForURLAndTitle(location, url_,
         text(), profile_);
     return !tooltip->empty();
   }
 
   virtual bool IsTriggerableEvent(const views::MouseEvent& e) OVERRIDE {
     return event_utils::IsPossibleDispositionEvent(e);
   }
@@ skipping 28 matching lines @@
     show_animation_.reset(new ui::SlideAnimation(this));
     if (BookmarkBarView::testing_) {
       // For some reason during testing the events generated by animating
       // throw off the test. So, don't animate while testing.
       show_animation_->Reset(1);
     } else {
       show_animation_->Show();
     }
   }
 
+  virtual bool GetTooltipText(const gfx::Point& p,
+                              std::wstring* tooltip) OVERRIDE {
+    if (text_size_.width() > GetTextBounds().width())
+      *tooltip = text_;
+    return !tooltip->empty();
+  }
+
   virtual bool IsTriggerableEvent(const views::MouseEvent& e) OVERRIDE {
     // Left clicks should show the menu contents and right clicks should show
     // the context menu. They should not trigger the opening of underlying urls.
     if (e.flags() == ui::EF_LEFT_BUTTON_DOWN ||
         e.flags() == ui::EF_RIGHT_BUTTON_DOWN)
       return false;
 
     WindowOpenDisposition disposition(
         event_utils::DispositionFromEventFlags(e.flags()));
     return disposition != CURRENT_TAB;
@@ skipping 1538 matching lines @@
               (1 - size_animation_->GetCurrentValue())));
     } else {
       prefsize.set_height(
           static_cast<int>(
               browser_defaults::kBookmarkBarHeight *
               size_animation_->GetCurrentValue()));
     }
   }
   return prefsize;
 }