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

tests/PDFJpegEmbedTest.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDocument.h"
 #include "SkCanvas.h"
 #include "SkImageGenerator.h"
 #include "SkData.h"
 #include "SkStream.h"
 
 #include "Resources.h"
 #include "Test.h"
 
+#if SK_SUPPORT_PDF
+
 // Returned bitmap is lazy.  Only lazy bitmaps hold onto the original data.
 static SkBitmap bitmap_from_data(SkData* data) {
     SkASSERT(data);
     SkBitmap bm;
     SkInstallDiscardablePixelRef(data, &bm);
     return bm;
 }
 
 static bool is_subset_of(SkData* smaller, SkData* larger) {
     SkASSERT(smaller && larger);
@@ skipping 91 matching lines @@
         if (kTests[i].type != info.fType) {
             ERRORF(r, "%s failed jfif type test", kTests[i].path);
             continue;
         }
         if (r->verbose()) {
             SkDebugf("\nJpegIdentification: %s [%d x %d]\n", kTests[i].path,
                      info.fWidth, info.fHeight);
         }
     }
 }
+#endif  // SK_SUPPORT_PDF