Revert "Revert "Do not update the type of something we already know.""

This reverts commit 63107a804ce17db9789051e1fe310d99d1dae1cb.

bug:22116987

(cherry picked from commit f9a199571417b5a5a62d94d05a064077e14dd2c4)

Change-Id: Ia516f2cbce6d22df37f3a0854abdd0b54d3ea72d
diff --git a/compiler/optimizing/graph_checker.h b/compiler/optimizing/graph_checker.h
index b4314da..9284bb7 100644
--- a/compiler/optimizing/graph_checker.h
+++ b/compiler/optimizing/graph_checker.h
@@ -48,6 +48,10 @@
   // Check that the HasBoundsChecks() flag is set for bounds checks.
   void VisitBoundsCheck(HBoundsCheck* check) OVERRIDE;
 
+  // Check that HCheckCast and HInstanceOf have HLoadClass as second input.
+  void VisitCheckCast(HCheckCast* check) OVERRIDE;
+  void VisitInstanceOf(HInstanceOf* check) OVERRIDE;
+
   // Was the last visit of the graph valid?
   bool IsValid() const {
     return errors_.empty();