Remove base's implicit_cast.

base/memory/scoped_ptr.h

Index: base/memory/scoped_ptr.h
diff --git a/base/memory/scoped_ptr.h b/base/memory/scoped_ptr.h
index 987ccfa804eadde2f89b1ac904ee77bd47b16d36..fb781b0b32ddfd8b47ff3e4a0662ff53b9cd8760 100644
--- a/base/memory/scoped_ptr.h
+++ b/base/memory/scoped_ptr.h
@@ -465,9 +465,7 @@ class scoped_ptr<T[], D> {
   //   (C++98 [expr.delete]p3). If you're doing this, fix your code.
   // - it cannot be const-qualified differently from T per unique_ptr spec
   //   (http://cplusplus.github.com/LWG/lwg-active.html#2118). Users wanting
-  //   to work around this may use implicit_cast<const T*>().
-  //   However, because of the first bullet in this comment, users MUST
-  //   NOT use implicit_cast<Base*>() to upcast the static type of the array.
+  //   to work around this may use const_cast<const T*>().
   explicit scoped_ptr(element_type* array) : impl_(array) {}
 
   // Constructor.  Allows construction from a nullptr.