Add ipc_mojo_perftests

This change adds ipc_mojo_perftests that runs the same benchmark
as of ipc_perftests. Now head-to-head comparison becomes possible.

For this change, whole ipc_perftests logic is extracted to
ipc_perftest_support.cc to make it reusable by ipc_mojo_perftests.

TEST=none
BUG=none
R=jam@chromium.org, darin@chromium.org, yuzhu@chromium.org

Review URL: https://codereview.chromium.org/536213002

Cr-Commit-Position: refs/heads/master@{#293988}

• ipc/BUILD.gn[diff]
• ipc/ipc.gyp[diff]
• ipc/ipc_channel.h[diff]
• ipc/ipc_channel_factory.h[diff]
• ipc/ipc_perftest_support.cc[Added - diff]
• ipc/ipc_perftest_support.h[Added - diff]
• ipc/ipc_perftests.cc[diff]
• ipc/ipc_test_base.cc[diff]
• ipc/ipc_test_base.h[diff]
• ipc/mojo/BUILD.gn[diff]
• ipc/mojo/ipc_channel_mojo.cc[diff]
• ipc/mojo/ipc_channel_mojo.h[diff]
• ipc/mojo/ipc_channel_mojo_unittest.cc[diff]
• ipc/mojo/ipc_mojo.gyp[diff]
• ipc/mojo/ipc_mojo_perftest.cc[Added - diff]