BUILD.gn: skia_enable_pdf

BUG=skia:

Change-Id: Icf616bec73e81aad97815b519566ff5b9db611e3
Reviewed-on: https://skia-review.googlesource.com/6495
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/tests/PDFPrimitivesTest.cpp b/tests/PDFPrimitivesTest.cpp
index 81b33ba..de9af07 100644
--- a/tests/PDFPrimitivesTest.cpp
+++ b/tests/PDFPrimitivesTest.cpp
@@ -5,6 +5,10 @@
  * found in the LICENSE file.
  */
 
+#include "Test.h"
+
+#ifdef SK_SUPPORT_PDF
+
 #include "Resources.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ -24,7 +28,6 @@
 #include "SkSpecialImage.h"
 #include "SkStream.h"
 #include "SkTypes.h"
-#include "Test.h"
 #include "sk_tool_utils.h"
 
 #include <cstdlib>
@@ -486,3 +489,4 @@
         REPORTER_ASSERT(reporter, roundTrip == i);
     }
 }
+#endif