Reland again [Startup Tracing] Add --trace-config-file flag

Original CL: https://codereview.chromium.org/1315463002/
1st reland: https://codereview.chromium.org/1317333002/

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This CL adds --trace-config-file flag. Please see trace_config_file.h for details.

Design doc:
https://docs.google.com/document/d/1PgdXUOJF3WtEmYWUyGRbC2Fz2ICCZKO9jPvpLPRSHH8/edit?usp=sharing

BUG=317481, 482098
TBR=dsinclair@chromium.org,blundell@chromium.org,sievers@chromium.org,sky@chromium.org,msw@chromium.org

Review URL: https://codereview.chromium.org/1309243004

Cr-Commit-Position: refs/heads/master@{#346407}


CrOS-Libchrome-Original-Commit: c074d28f557ee0996efb3aa584b8932e1beb837e
1 file changed
tree: 64a94683f55af75e977e158c2ee482f23b6e92dc
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/