Add Windows build flags
Add Windows build flags

Step 0 for supporting building Perfetto (only in the context of the
Chromium tree) is adding PERFETTO_BUILDFLAG_DEFINE_PERFETTO_OS_WIN.

Change-Id: I2d2067df671043d3697337b1528d4c1acc70821f
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto