Ignore filtered event if an event matcher cannot be added.

BUG=625404

Review-Url: https://codereview.chromium.org/2236133002
Cr-Commit-Position: refs/heads/master@{#411472}
(cherry picked from commit ba011d9f8322c62633a069a59c2c5525e3ff46cc)

Review URL: https://codereview.chromium.org/2250433002 .

Cr-Commit-Position: refs/branch-heads/2785@{#601}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}
1 file changed