blink: Reduce the size of local_frame_view.h

This CL reduces estimated expanded size of local_frame_view.h from 8.0MB
to 3.0MB.
FYI: local_frame_view.h is used in 2,400+ compilation units.

- To avoid including chrome_client.h, GetChromeClient() returns
  PlatformChromeClient.
  It overrides ScrollableArea::GetChromeClient(), which returns
  PlatformChromeClient.
  Introduce ToChromeClient(PlatformChromeClient*)

- To avoid including first_meaningful_paint_detector.h, split
  LayoutObjectCounter out from first_meaningful_paint_detector.h.

Bug: 242216
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I14ad29eb359ed8e1b0506f91674e85e8704f8b8e
Reviewed-on: https://chromium-review.googlesource.com/1100726
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567547}
34 files changed