Refactoring installer shortcut deletion; adding dedicated shortcut update feature.

base/base_paths_win.cc

Index: base/base_paths_win.cc
diff --git a/base/base_paths_win.cc b/base/base_paths_win.cc
index f4dd434349d89ff222c73986dee5ac8c4e5400e7..1cdba68452277a5baadff5b269d306d9763bd2a3 100644
--- a/base/base_paths_win.cc
+++ b/base/base_paths_win.cc
@@ -195,6 +195,9 @@ bool PathProviderWin(int key, FilePath* result) {
         return false;
       break;
     case base::DIR_TASKBAR_PINS:
+      if (win::GetVersion() < win::VERSION_WIN7)
+        return false;
+
       if (!PathService::Get(base::DIR_USER_QUICK_LAUNCH, &cur))
         return false;
       cur = cur.AppendASCII("User Pinned");