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

tests/FlateTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkData.h"
 #include "SkFlate.h"
 #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 {
 public:
     virtual size_t read(void* buffer, size_t size) {
         if (buffer == NULL && size == 0)
             return 0;
         if (buffer == NULL && size == kGetSizeKey)
             size = 0;
         return SkMemoryStream::read(buffer, size);
@@ skipping 82 matching lines @@
 
 DEF_TEST(Flate, reporter) {
     SkMemoryStream memStream;
     TestFlate(reporter, &memStream, 512);
     TestFlate(reporter, &memStream, 10240);
 
     SkZeroSizeMemStream fileStream;
     TestFlate(reporter, &fileStream, 512);
     TestFlate(reporter, &fileStream, 10240);
 }
+#endif  // SK_SUPPORT_PDF