Delete both regular and Metro user data dirs on uninstall.

chrome/installer/util/product.h

Index: chrome/installer/util/product.h
diff --git a/chrome/installer/util/product.h b/chrome/installer/util/product.h
index eabc3c9cc5be73417f86bef0f8b30fc3557986ec..aed199dfbed8af23ac601c8c8178195d8c10cf53 100644
--- a/chrome/installer/util/product.h
+++ b/chrome/installer/util/product.h
@@ -76,11 +76,15 @@ class Product {
       return options_.erase(option) != 0;
   }
 
-  // Returns the path to the directory that holds the user data.  This is always
-  // inside "Users\<user>\Local Settings".  Note that this is the default user
-  // data directory and does not take into account that it can be overriden with
-  // a command line parameter.
-  FilePath GetUserDataPath() const;
+  // Returns the path(s) to the directory that holds the user data (primary
+  // and, if applicable to |dist|, alternate).  This is always inside a user's
+  // local application data folder (e.g., "AppData\Local or "Local
+  // Settings\Application Data" in %USERPROFILE%). Note that these are the
+  // defaults and do not take into account that they can be overriden with a
+  // command line parameter.  |paths| may be empty on return, but is guaranteed
+  // not to contain empty paths otherwise. If more than one path is returned,
+  // they are guaranteed to be siblings.
+  void GetUserDataPaths(std::vector<FilePath>* paths) const;
 
   // Launches Chrome without waiting for it to exit.
   bool LaunchChrome(const FilePath& application_path) const;