SkPDF: allow PDF module to be disabled in DM and SampleApp

tests/FlateTest.cpp

Index: tests/FlateTest.cpp
diff --git a/tests/FlateTest.cpp b/tests/FlateTest.cpp
index 40efe1a5d85f9ff8f2e414a11292b961f6abc883..8387f527d120eb1ffe9d6aef6745030087bf0fec 100644
--- a/tests/FlateTest.cpp
+++ b/tests/FlateTest.cpp
@@ -10,6 +10,8 @@
 #include "SkStream.h"
 #include "Test.h"
 
+#if SK_SUPPORT_PDF
+
 // A memory stream that reports zero size with the standard call, like
 // an unseekable file stream would.
 class SkZeroSizeMemStream : public SkMemoryStream {
@@ -112,3 +114,4 @@ DEF_TEST(Flate, reporter) {
     TestFlate(reporter, &fileStream, 512);
     TestFlate(reporter, &fileStream, 10240);
 }
+#endif  // SK_SUPPORT_PDF