Web MIDI: make unsupported device check strict
Web MIDI: make unsupported device check strict

Some hardware devices seem to report the same MID and PID with the
blacklisted software synth. This patch adds one more check to
disable only software synth.

BUG=512318
TBR=yukawa@chromium.org

Review URL: https://codereview.chromium.org/1241413002

Cr-Commit-Position: refs/heads/master@{#339621}
(cherry picked from commit 7f258c184e269772364d4f21a1c1fbf3b514381d)

Review URL: https://codereview.chromium.org/1242873006 .

Cr-Commit-Position: refs/branch-heads/2454@{#103}
Cr-Branched-From: 12bfc3360892ec53cd00fc239a47e5298beb063b-refs/heads/master@{#338390}
(cherry picked from commit 829a4112896961371de86570733904169ea6443b)

Review URL: https://codereview.chromium.org/1259493002 .

Cr-Commit-Position: d34a0005849006230ae7ffb1a9693419810a06bc@{#560}
Cr-Branched-From: 40cda19e609fd36fbf5fe489055423e611631abc@{#330231}

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