[libfuzzer] Add fuzzer for third_party/hunspell with dictionary.

third_party/hunspell/BUILD.gn

Index: third_party/hunspell/BUILD.gn
diff --git a/third_party/hunspell/BUILD.gn b/third_party/hunspell/BUILD.gn
index d086c00d8ba6090de96997df13f326c33e73bdac..c6abd33c16902fbe8d0142f82de2222c5ad26fba 100644
--- a/third_party/hunspell/BUILD.gn
+++ b/third_party/hunspell/BUILD.gn
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//testing/libfuzzer/fuzzer_test.gni")
+
 config("hunspell_config") {
   defines = [
     "HUNSPELL_STATIC",
@@ -109,3 +111,13 @@ source_set("hunspell") {
     ]
   }
 }
+
+fuzzer_test("hunspell_fuzzer") {
+  sources = [
+    "fuzz/hunspell_fuzzer.cc",

[please use gerrit instead, 2016/06/01 17:09:17]

Sources should include the header files, too. You would want changes in your
headers to cause a rebuild as well.

[mmoroz, 2016/06/02 10:54:36]

Done.

+  ]
+  deps = [
+    ":hunspell",
+  ]
+  dict = "fuzz/hunspell.dict"

[please use gerrit instead, 2016/06/01 17:09:17]

Either here or inside of hunspell.dict, explain that this "dict" is not a
spellcheck dictionary. It's confusing, because you're fuzzing a spellcheck
library, which has its own definition of what a dictionary is.

[mmoroz, 2016/06/02 10:54:35]

Done.

+}