Code: FileReaderLoader::FileReaderLoader(ReadType read_type,
                                   FileReaderLoaderClient* client)
    : read_type_(read_type),
      client_(client),
       handle_watcher_(FROM_HERE, mojo::SimpleWatcher::ArmingPolicy::AUTOMATIC),
      binding_(this) {}

Vulnerability Type: 
CWE ID: CWE-416
Summary: A use after free in Blink in Google Chrome prior to 67.0.3396.62 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
Commit Message: Fix use-after-free in FileReaderLoader.

Anything that calls out to client_ can cause FileReaderLoader to be
destroyed, so make sure to check for that situation.

Bug: 835639
Change-Id: I57533d41b7118c06da17abec28bbf301e1f50646
Reviewed-on: https://chromium-review.googlesource.com/1024450
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Commit-Queue: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552807}