Ensure that data doesn't leak between users on cros chrome crash.

chrome/browser/chromeos/cros/cryptohome_library.h

Index: chrome/browser/chromeos/cros/cryptohome_library.h
diff --git a/chrome/browser/chromeos/cros/cryptohome_library.h b/chrome/browser/chromeos/cros/cryptohome_library.h
index 1bec9fad837513a4395f22fbb53e8e8f4ffc8d3c..7fab7e643dd9fd1cf63e73e99a2a056f293ca630 100644
--- a/chrome/browser/chromeos/cros/cryptohome_library.h
+++ b/chrome/browser/chromeos/cros/cryptohome_library.h
@@ -31,6 +31,9 @@ class CryptohomeLibrary {
   virtual bool CheckKey(const std::string& user_email,
                         const std::string& passhash);
 
+  // Asks cryptohomed if a drive is currently mounted.
+  virtual bool IsMounted();
+
  private:
   friend struct DefaultSingletonTraits<CryptohomeLibrary>;
   friend class MockCryptohomeLibrary;