Clean up code to clarify we are only tracking the condition flags of APSR.

src/trusted/validator_arm/inst_classes.h

Index: src/trusted/validator_arm/inst_classes.h
===================================================================
--- src/trusted/validator_arm/inst_classes.h	(revision 8564)
+++ src/trusted/validator_arm/inst_classes.h	(working copy)
@@ -223,21 +223,22 @@
 };
 
 // Interface class to pull out S (update) bit from bit 20, which
-// defines if the flags register is updated by the instruction.
-class UpdatesFlagsRegisterBit20Interface {
+// defines if the condition bits in APSR are updated by the instruction.
+class UpdatesConditionsBit20Interface {
  public:
-  inline UpdatesFlagsRegisterBit20Interface() {}
-  // Returns true if bit is set that states that the flags register is updated.
+  inline UpdatesConditionsBit20Interface() {}
+  // Returns true if bit is set that states that the condition bits
+  // APSR is updated.
   static inline bool is_updated(const Instruction i) {
     return i.bit(20);
   }
-  // Returns the flags register if it is used.
-  static inline Register reg_if_updated(const Instruction i) {
-    return is_updated(i) ? kRegisterFlags : kRegisterNone;
+  // Returns the conditions register if it is used.
+  static inline Register conds_if_updated(const Instruction i) {
+    return is_updated(i) ? kConditions : kRegisterNone;
   }
 
  private:
-  NACL_DISALLOW_COPY_AND_ASSIGN(UpdatesFlagsRegisterBit20Interface);
+  NACL_DISALLOW_COPY_AND_ASSIGN(UpdatesConditionsBit20Interface);
 };
 
 // A class decoder is designed to decode a set of instructions that