Type check the m_pShadingObj before assuming it's a stream.

pdfium.gyp

 {
   'variables': {
     'pdf_use_skia%': 0,
     'pdf_enable_v8%': 1,
     'conditions': [
       ['OS=="linux"', {
         'bundle_freetype%': 0,
       }, {  # On Android there's no system FreeType. On Windows and Mac, only a
             # few methods are used from it.
         'bundle_freetype%': 1,
@@ skipping 724 matching lines @@
         '<(DEPTH)/testing/gtest.gyp:gtest',
         'pdfium',
         'test_support',
       ],
       'include_dirs': [
         '<(DEPTH)',
       ],
       'sources': [
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_embeddertest.cpp',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_parser_embeddertest.cpp',
+        'core/src/fpdfapi/fpdf_render/fpdf_render_pattern_embeddertest.cpp',
         'fpdfsdk/src/fpdf_dataavail_embeddertest.cpp',
         'fpdfsdk/src/fpdfdoc_embeddertest.cpp',
         'fpdfsdk/src/fpdfformfill_embeddertest.cpp',
         'fpdfsdk/src/fpdftext_embeddertest.cpp',
         'fpdfsdk/src/fpdfview_c_api_test.c',
         'fpdfsdk/src/fpdfview_c_api_test.h',
         'fpdfsdk/src/fpdfview_embeddertest.cpp',
         'testing/embedder_test.cpp',
         'testing/embedder_test.h',
         'testing/embedder_test_mock_delegate.h',
@@ skipping 39 matching lines @@
           ],
           'dependencies': [
             '<(DEPTH)/v8/tools/gyp/v8.gyp:v8',
             '<(DEPTH)/v8/tools/gyp/v8.gyp:v8_libplatform',
           ],
         }],
       ],
     },
   ],
 }