PolicyManager: Disallow copy and assign on Variable objects.

Per style guide, we don't allow copy constructors on objects that
don't need to be copied.

BUG=None
TEST=Build and unittest.

Change-Id: Ib6efcc8ad9860394239d84216f730a4896cf78f9
Reviewed-on: https://chromium-review.googlesource.com/191077
Reviewed-by: Gilad Arnold <[email protected]>
Commit-Queue: Alex Deymo <[email protected]>
Tested-by: Alex Deymo <[email protected]>
diff --git a/policy_manager/fake_variable.h b/policy_manager/fake_variable.h
index 36c3848..b1de9d2 100644
--- a/policy_manager/fake_variable.h
+++ b/policy_manager/fake_variable.h
@@ -53,6 +53,8 @@
  private:
   // The pointer returned by GetValue().
   scoped_ptr<const T> ptr_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeVariable);
 };
 
 }  // namespace chromeos_policy_manager