Don't attempt to forward declare StringPiece.

1) This is discouraged because it prevents callers from benefiting from automatic coersion from string/char* types.
2) A follow-up CL (http://codereview.chromium.org/8659047/) will make StringPiece a template, and thus awkward to forward declare. The very small number of places that were appropriately forward declaring it do not justify writing a 'string_piece_forward.h'.

BUG=87634
R=cbentzel@chromium.org


Review URL: http://codereview.chromium.org/8929002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114219 0039d316-1c4b-4281-b951-d872f2087c98

net/base/big_endian.h

@@ -7,12 +7,9 @@
 #pragma once
 
 #include "base/basictypes.h"
+#include "base/string_piece.h"
 #include "net/base/net_export.h"
 
-namespace base {
-class StringPiece;
-}
-
 namespace net {
 
 // Read an integer (signed or unsigned) from |buf| in Big Endian order.

net/dns/dns_client.h

@@ -11,12 +11,9 @@
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "base/string_piece.h"
 #include "net/base/net_export.h"
 
-namespace base {
-class StringPiece;
-}
-
 namespace net {
 
 class BoundNetLog;