base: Change DCHECK_IS_ON to a macro DCHECK_IS_ON().

This ensures that if the header is not included, and a DCHECK is guarded
by this check, that the file will fail to compile instead of silently
compiling the DCHECK out.

For example:

#if DCHECK_IS_ON
DCHECK(SomeThing());
#endif

This example would be compiled out if DCHECK_IS_ON was not defined due
to not including the logging.h header.

Instead, this will fail to compile:

#if DCHECK_IS_ON()
DCHECK(SomeThing());
#endif

[email protected]

Review URL: https://codereview.chromium.org/842523002

Cr-Commit-Position: refs/heads/master@{#310626}
diff --git a/extensions/renderer/logging_native_handler.h b/extensions/renderer/logging_native_handler.h
index 052b23d..7ae7ef51 100644
--- a/extensions/renderer/logging_native_handler.h
+++ b/extensions/renderer/logging_native_handler.h
@@ -28,7 +28,7 @@
   // void(predicate, message?)
   void Dcheck(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  // Equivalent to DCHECK_IS_ON.
+  // Equivalent to DCHECK_IS_ON().
   //
   // bool()
   void DcheckIsOn(const v8::FunctionCallbackInfo<v8::Value>& args);