Add fuzzer for cmap parsing

testing/libfuzzer/BUILD.gn

 # Copyright 2016 The PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../../pdfium.gni")
 
 config("libfuzzer_config") {
   configs = [ "//third_party/pdfium:pdfium_core_config" ]
 
   defines = [
@@ skipping 136 matching lines @@
       "//third_party/pdfium:pdfium",
     ]
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [
       "//build/config/compiler:no_chromium_code",
       ":libfuzzer_config",
     ]
   }
 }
 
+source_set("pdf_cmap_fuzzer") {
+  testonly = true
+  sources = [
+    "pdf_cmap_fuzzer.cc",
+  ]
+  deps = [
+    "//third_party/pdfium:pdfium",
+  ]
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [
+    "//build/config/compiler:no_chromium_code",
+    ":libfuzzer_config",
+  ]
+}
+
 source_set("pdf_codec_fax_fuzzer") {
   testonly = true
   sources = [
     "pdf_codec_fax_fuzzer.cc",
   ]
   deps = [
     "//third_party/pdfium:pdfium",
   ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
@@ skipping 69 matching lines @@
   ]
   deps = [
     "//third_party/pdfium:pdfium",
   ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
     "//build/config/compiler:no_chromium_code",
     ":libfuzzer_config",
   ]
 }