Delete both regular and Metro user data dirs on uninstall.

chrome/installer/util/product.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_INSTALLER_UTIL_PRODUCT_H_
 #define CHROME_INSTALLER_UTIL_PRODUCT_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 58 matching lines @@
   }
 
   // Returns true if the set of options is mutated by this operation.
   bool SetOption(const std::wstring& option, bool set) {
     if (set)
       return options_.insert(option).second;
     else
       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;
 
   // Launches Chrome with given command line, waits for Chrome indefinitely
   // (until it terminates), and gets the process exit code if available.
   // The function returns true as long as Chrome is successfully launched.
   // The status of Chrome at the return of the function is given by exit_code.
   // NOTE: The 'options' CommandLine object should only contain parameters.
   // The program part will be ignored.
@@ skipping 34 matching lines @@
   scoped_ptr<ProductOperations> operations_;
   std::set<std::wstring> options_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Product);
 };
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_PRODUCT_H_