empty impl of webthemeengine::getSize for test_shell

webkit/tools/test_shell/test_shell_webthemeengine.cc

Index: webkit/tools/test_shell/test_shell_webthemeengine.cc
diff --git a/webkit/tools/test_shell/test_shell_webthemeengine.cc b/webkit/tools/test_shell/test_shell_webthemeengine.cc
index ae0974d9a9887ac1473edbcf4f3fdc9c1d59b56b..3d56e70abcbcdf783fed4a2710d7d2b4d97e9a50 100644
--- a/webkit/tools/test_shell/test_shell_webthemeengine.cc
+++ b/webkit/tools/test_shell/test_shell_webthemeengine.cc
@@ -569,4 +569,8 @@ void Engine::paintProgressBar(WebKit::WebCanvas* canvas,
   drawProgressBar(canvas, ctype, cstate, barRect, valueRect);
 }
 
+WebKit::WebSize Engine::getSize(int part) {
+  return WebKit::WebSize();
+}
+
 }  // namespace TestShellWebTheme