Add more seed corpora to pdf_codec_png_fuzzer.

pdf/pdfium/fuzzers/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # PDFium fuzzers.
 
 import("//third_party/pdfium/pdfium.gni")
 import("//testing/test.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
@@ skipping 115 matching lines @@
     dict = "dicts/pdf_codec_jpeg.dict"
     seed_corpus = "corpora/pdf_codec_jpeg"
   }
 
   fuzzer_test("pdf_codec_png_fuzzer") {
     sources = []
     deps = [
       "//third_party/pdfium/testing/libfuzzer:pdf_codec_png_fuzzer",
     ]
     dict = "dicts/pdf_codec_png.dict"
-    seed_corpus = "corpora/pdf_codec_png"
+    seed_corpuses = [
+      "corpora/pdf_codec_png",
+      "//cc/test/data",
+      "//third_party/WebKit/LayoutTests/images/png-suite/samples",
+      "//third_party/WebKit/LayoutTests/images/resources/pngfuzz",
+    ]
   }
 
   fuzzer_test("pdf_codec_tiff_fuzzer") {
     sources = []
     deps = [
       "//third_party/pdfium/testing/libfuzzer:pdf_codec_tiff_fuzzer",
     ]
     dict = "dicts/pdf_codec_tiff.dict"
     seed_corpus = "corpora/pdf_codec_tiff"
   }
@@ skipping 23 matching lines @@
   }
 
   fuzzer_test("pdf_cfx_saxreader_fuzzer") {
     sources = []
     deps = [
       "//third_party/pdfium/testing/libfuzzer:pdf_cfx_saxreader_fuzzer",
     ]
     dict = "dicts/pdf_xml.dict"
   }
 }