Add download item tooltips on linux/win.

chrome/browser/views/download_item_view.h

Index: chrome/browser/views/download_item_view.h
diff --git a/chrome/browser/views/download_item_view.h b/chrome/browser/views/download_item_view.h
index 4c1526c72b0e88012cc0658d7df638941f150fdf..366dc1c7630b5c7d4705831ae3d173b00f54cb50 100644
--- a/chrome/browser/views/download_item_view.h
+++ b/chrome/browser/views/download_item_view.h
@@ -114,6 +114,8 @@ class DownloadItemView : public views::ButtonListener,
 
   void LoadIcon();
 
+  virtual bool GetTooltipText(const gfx::Point& p, std::wstring* tooltip);
+
   // Convenience method to paint the 3 vertical bitmaps (bottom, middle, top)
   // that form the background.
   void PaintBitmaps(gfx::Canvas* canvas,
@@ -176,6 +178,9 @@ class DownloadItemView : public views::ButtonListener,
   // The font used to print the file name and status.
   gfx::Font font_;
 
+  // The tooltip.
+  std::wstring tooltip_text_;
+
   // The current state (normal, hot or pushed) of the body and drop-down.
   State body_state_;
   State drop_down_state_;