Fix presumbit errors in previous commit

src/debug.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 934 matching lines @@
   // The previous state of the disable break used to restore the value when this
   // object is destructed.
   bool prev_disable_break_;
 };
 
 
 // Debug_Address encapsulates the Address pointers used in generating debug
 // code.
 class Debug_Address {
  public:
-  Debug_Address(Debug::AddressId id) : id_(id) { }
+  explicit Debug_Address(Debug::AddressId id) : id_(id) { }
 
   static Debug_Address AfterBreakTarget() {
     return Debug_Address(Debug::k_after_break_target_address);
   }
 
   static Debug_Address DebugBreakReturn() {
     return Debug_Address(Debug::k_debug_break_return_address);
   }
 
   static Debug_Address RestarterFrameFunctionPointer() {
@@ skipping 40 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 #endif  // V8_DEBUG_H_