Bug 1008435 - Let the Gecko Profiler work with child processes. r=BenWa,smaug.

We now allow profiling the content process for e10s, and plugin processes.

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extra : rebase_source : 1f2e35d4d55b33b56160132893dbf7d4787925fa
extra : amend_source : d03465d4318f8e50c7624ad0eeb681b30c068b11