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

tests/ToUnicodeTest.cpp

 /*
  * Copyright 2010 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkData.h"
 #include "SkPDFFont.h"
 #include "SkPDFTypes.h"
 #include "SkStream.h"
 #include "Test.h"
 
+#if SK_SUPPORT_PDF
+
 static bool stream_equals(const SkDynamicMemoryWStream& stream, size_t offset,
                           const char* buffer, size_t len) {
     SkAutoDataUnref data(stream.copyToData());
     if (offset + len > data->size()) {
         return false;
     }
     if (len != strlen(buffer)) {
         return false;
     }
     return memcmp(data->bytes() + offset, buffer, len) == 0;
@@ skipping 147 matching lines @@
 <004F> <006C>\n\
 <0051> <006E>\n\
 endbfchar\n\
 1 beginbfrange\n\
 <0056> <0057> <0073>\n\
 endbfrange\n";
 
     REPORTER_ASSERT(reporter, stream_equals(buffer2, 0, expectedResult2,
                                             buffer2.getOffset()));
 }
+#endif  // SK_SUPPORT_PDF