Code: std::string TestURLLoader::TestUntendedLoad() {
  pp::URLRequestInfo request(instance_);
  request.SetURL("test_url_loader_data/hello.txt");
  request.SetRecordDownloadProgress(true);
  TestCompletionCallback callback(instance_->pp_instance(), callback_type());

  pp::URLLoader loader(instance_);
  callback.WaitForResult(loader.Open(request, callback.GetCallback()));
  CHECK_CALLBACK_BEHAVIOR(callback);
  ASSERT_EQ(PP_OK, callback.result());

  int64_t bytes_received = 0;
  int64_t total_bytes_to_be_received = 0;
  while (true) {
     loader.GetDownloadProgress(&bytes_received, &total_bytes_to_be_received);
     if (total_bytes_to_be_received <= 0)
       return ReportError("URLLoader::GetDownloadProgress total size",
          total_bytes_to_be_received);
     if (bytes_received == total_bytes_to_be_received)
       break;
    if (pp::Module::Get()->core()->IsMainThread()) {
      NestedEvent event(instance_->pp_instance());
      event.PostSignal(10);
      event.Wait();
    }
  }
  std::string body;
  std::string error = ReadEntireResponseBody(&loader, &body);
  if (!error.empty())
    return error;
  if (body != "hello\n")
    return ReportError("Couldn't read data", callback.result());

  PASS();
}

Vulnerability Type: Bypass 
CWE ID: CWE-284
Summary: Blink, as used in Google Chrome before 51.0.2704.63, allows remote attackers to bypass the Same Origin Policy by leveraging the mishandling of Document reattachment during destruction, related to FrameLoader.cpp and LocalFrame.cpp.
Commit Message: Fix one implicit 64-bit -> 32-bit implicit conversion in a PPAPI test.

../../ppapi/tests/test_url_loader.cc:877:11: warning: implicit conversion loses integer precision: 'int64_t' (aka 'long long') to 'int32_t' (aka 'int') [-Wshorten-64-to-32]
          total_bytes_to_be_received);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~

BUG=879657

Change-Id: I152f456368131fe7a2891ff0c97bf83f26ef0906
Reviewed-on: https://chromium-review.googlesource.com/c/1220173
Commit-Queue: Raymes Khoury <raymes@chromium.org>
Reviewed-by: Raymes Khoury <raymes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600182}