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

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

Index: chrome/browser/ui/views/bookmarks/bookmark_bar_view.cc
===================================================================
--- chrome/browser/ui/views/bookmarks/bookmark_bar_view.cc	(revision 91698)
+++ chrome/browser/ui/views/bookmarks/bookmark_bar_view.cc	(working copy)
@@ -146,7 +146,8 @@
     }
   }
 
-  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_,
@@ -195,6 +196,13 @@
     }
   }
 
+  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.