commit 87dc11bdb4e1cf4ba674f3907fa1127f8839ad40
author kouhei <kouhei@chromium.org> Tue May 16 23:28:20 2017
committer Commit bot <commit-bot@chromium.org> Tue May 16 23:28:20 2017
tree c4666d79a8c22032c02165fa449ea13adcef3e67
parent 5d609a1b0650829208d50d74c26d4dd8dd8e9dd7

[ES6 modules] ModuleTreeLinker::Instantiate shouldn't proceed on invalid context

Before this CL, ModuleTreeLinker::Instantiate assumed that it is only called for
modulator with a valid context. However, asynchronous module graph node load
completion may be triggered after the context was destroyed.

This CL fixes the issue by making ModuleTreeLinker::Instantiate fail without crashing
if the context is invalid.

BUG=594639,716935

Review-Url: https://codereview.chromium.org/2886593002
Cr-Commit-Position: refs/heads/master@{#472246}