third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/arena_test_util.h

Index: third_party/protobuf/src/google/protobuf/arena_test_util.h
diff --git a/third_party/protobuf/src/google/protobuf/arena_test_util.h b/third_party/protobuf/src/google/protobuf/arena_test_util.h
index 690cc706ee5f2d029752fe6f1b323130046938e5..8c9f7698c5da6cd2fd25e57cf38afc34ce718e9d 100644
--- a/third_party/protobuf/src/google/protobuf/arena_test_util.h
+++ b/third_party/protobuf/src/google/protobuf/arena_test_util.h
@@ -31,9 +31,40 @@
 #ifndef GOOGLE_PROTOBUF_ARENA_TEST_UTIL_H__
 #define GOOGLE_PROTOBUF_ARENA_TEST_UTIL_H__
 
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/arena.h>
 
 namespace google {
 namespace protobuf {
+
+template <typename T, bool use_arena>
+void TestParseCorruptedString(const T& message) {
+  int success_count = 0;
+  string s = message.SerializeAsString();
+  const int kMaxIters = 900;
+  const int stride = s.size() <= kMaxIters ? 1 : s.size() / kMaxIters;
+  const int start = stride == 1 || use_arena ? 0 : (stride + 1) / 2;
+  for (int i = start; i < s.size(); i += stride) {
+    for (int c = 1 + (i % 17); c < 256; c += 2 * c + (i & 3)) {
+      s[i] ^= c;
+      google::protobuf::Arena arena;
+      T* message =
+          google::protobuf::Arena::CreateMessage<T>(use_arena ? &arena : NULL);
+      if (message->ParseFromString(s)) {
+        ++success_count;
+      }
+      if (!use_arena) {
+        delete message;
+      }
+      s[i] ^= c;  // Restore s to its original state.
+    }
+  }
+  // This next line is a low bar.  But getting through the test without crashing
+  // due to use-after-free or other bugs is a big part of what we're checking.
+  GOOGLE_CHECK_GT(success_count, 0);
+}
+
 namespace internal {
 
 class NoHeapChecker {