Rework tree APIs to reflect Google style and more const-correctness....

chrome/browser/ui/views/download_item_view.cc

Index: chrome/browser/ui/views/download_item_view.cc
===================================================================
--- chrome/browser/ui/views/download_item_view.cc	(revision 74231)
+++ chrome/browser/ui/views/download_item_view.cc	(working copy)
@@ -393,7 +393,7 @@
   // We use the parent's (DownloadShelfView's) SchedulePaint, since there
   // are spaces between each DownloadItemView that the parent is responsible
   // for painting.
-  GetParent()->SchedulePaint();
+  parent()->SchedulePaint();
 }
 
 void DownloadItemView::OnDownloadOpened(DownloadItem* download) {
@@ -961,7 +961,7 @@
 void DownloadItemView::OnExtractIconComplete(IconManager::Handle handle,
                                              SkBitmap* icon_bitmap) {
   if (icon_bitmap)
-    GetParent()->SchedulePaint();
+    parent()->SchedulePaint();
 }
 
 void DownloadItemView::LoadIcon() {