Don't attempt to forward declare StringPiece.

webkit/tools/test_shell/test_shell.h

Index: webkit/tools/test_shell/test_shell.h
diff --git a/webkit/tools/test_shell/test_shell.h b/webkit/tools/test_shell/test_shell.h
index 2d6baeff8ec1484a2cd0fe7b454fac69c7d3ef03..2085e635577195f9d97050541f052525c8fda502 100644
--- a/webkit/tools/test_shell/test_shell.h
+++ b/webkit/tools/test_shell/test_shell.h
@@ -35,6 +35,7 @@
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/scoped_temp_dir.h"
+#include "base/string_piece.h"
 #if defined(OS_MACOSX)
 #include "base/lazy_instance.h"
 #endif
@@ -57,10 +58,6 @@ class TestShellDevToolsAgent;
 class TestShellDevToolsClient;
 class TestWebViewDelegate;
 
-namespace base {
-class StringPiece;
-}
-
 namespace WebKit {
 class WebDeviceOrientationClientMock;
 class WebGeolocationClientMock;