DevTools: Suspend a new target when TargetManager._isSuspended is true

When DevTools start recording the performance timeline, TargetManager suspends
the all targets. But if a new target is added by createTarget, currently the new
target is not suspended.

This is problematic while measuring the performance of PWAFullCodeCache, because
V8 doesn't generate code cache if debugger is attached to the newly started
service worker.

Bug: 768705
Change-Id: Ib54f89123ce96187fcbcc390ba2713c00465abbb
Reviewed-on: https://chromium-review.googlesource.com/778706
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518506}
10 files changed