Rename buildflag_header targets in base for consistency

Targets go from foo_features to foo_buildflags
And similarly the header now has buildflags in the name.

BUG=814485
TEST=covered by build

Change-Id: Ib936c2840991902fa33c040b381b8ffc98a3c532
Reviewed-on: https://chromium-review.googlesource.com/930033
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538310}

CrOS-Libchrome-Original-Commit: 4416579b311cc64b476335b5d46ddbfa6131ed0e
28 files changed
tree: da3392c95a372878cd78a55baeb76c1270cabe29
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/