Do not create background thread if MDM is not initialized

If MDM is not initialized then a dump cannot be in progress. So,
OnHeapProfilingEnabled() can be called on any thread. Creating thread
at early startup causes crashes at sandbox initialization.

BUG=762994

Change-Id: Ia85fb6f1efbd4911b1ed56633b6af1c9bb201937
Reviewed-on: https://chromium-review.googlesource.com/655810
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Cr-Commit-Position: refs/heads/master@{#500732}

CrOS-Libchrome-Original-Commit: 2d505f417ed6cca3f0df6ebbd491527e59b4c2c3
3 files changed
tree: 57c95c9ef58a41efc31241c710749ed02ef572f0
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/