base: Fix/add header #ifndef guards.

base/debug/debugger.h

Index: base/debug/debugger.h
diff --git a/base/debug/debugger.h b/base/debug/debugger.h
index d62ea3f7e17b9b002280860cf63461b663a31d8c..8680e281ed1e7ddb64bc396acd036f83bb3bc15e 100644
--- a/base/debug/debugger.h
+++ b/base/debug/debugger.h
@@ -6,8 +6,8 @@
 // debuggers.  You should use this to test if you're running under a debugger,
 // and if you would like to yield (breakpoint) into the debugger.
 
-#ifndef BASE_DEBUG_DEBUGGER_H
-#define BASE_DEBUG_DEBUGGER_H
+#ifndef BASE_DEBUG_DEBUGGER_H_
+#define BASE_DEBUG_DEBUGGER_H_
 
 #include "base/base_export.h"
 
@@ -41,4 +41,4 @@ BASE_EXPORT bool IsDebugUISuppressed();
 }  // namespace debug
 }  // namespace base
 
-#endif  // BASE_DEBUG_DEBUGGER_H
+#endif  // BASE_DEBUG_DEBUGGER_H_