Add minidump fuzzer for breakpad.

testing/libfuzzer/fuzzer_test.gni

Index: testing/libfuzzer/fuzzer_test.gni
diff --git a/testing/libfuzzer/fuzzer_test.gni b/testing/libfuzzer/fuzzer_test.gni
index 8f1b8919e892988354c0422f2bae139f827c382e..ad013b0b10f0f0dca2d88d7d445cc0b2935dc91e 100644
--- a/testing/libfuzzer/fuzzer_test.gni
+++ b/testing/libfuzzer/fuzzer_test.gni
@@ -108,6 +108,7 @@ template("fuzzer_test") {
       forward_variables_from(invoker,
                              [
                                "check_includes",
+                               "defines",
                                "include_dirs",
                                "sources",
                              ])
@@ -144,6 +145,8 @@ template("fuzzer_test") {
       assert(invoker.seed_corpus == [] || invoker.seed_corpus != [])
     }
     assert(!defined(invoker.check_includes) || invoker.check_includes != [])
+    assert(!defined(invoker.include_dirs) || invoker.include_dirs != [])
+    assert(!defined(invoker.defines) || invoker.defines != [])
 
     group(target_name) {
     }