Fold analytic clip FPs into GrReducedClip

Perf result on Pixel phone (sorted by impact):

  GEOMEAN                              7.44 -> 6.92 ms   [ 93%]

  keymobi_cnn_com.skp                  3.55 -> 3.59 ms   [101%]
  keymobi_theverge_com.skp             4.08 -> 4.13 ms   [101%]
  desk_skbug6850autoscroll.skp         1.21 -> 1.22 ms   [101%]
  ...
  top25desk_weather_com.skp            14.2 -> 11.5 ms   [ 81%]
  keymobi_androidpolice_com_2012_.skp  3.84 -> 2.95 ms   [ 77%]
  keymobi_shop_mobileweb_ebay_com.skp  2.94 -> 2.26 ms   [ 77%]
  keymobi_boingboing_net.skp           3.08 -> 2.24 ms   [ 73%]
  desk_jsfiddlebigcar.skp              1.90 -> 1.25 ms   [ 66%]
  keymobi_m_youtube_com_watch_v_9.skp  13.5 -> 8.84 ms   [ 65%]
  keymobi_sfgate_com_.skp              8.55 -> 5.55 ms   [ 65%]
  keymobi_blogger.skp                  4.01 -> 2.60 ms   [ 65%]

Cleaner code, improved skps, slightly better geometric mean time.

Pixel C is mostly unaffected, presumably because it uses window
rectangles.

Bug: skia:7190
Change-Id: Ia93f68b2f971ea66b3ab19dc73557ea602932a92
Reviewed-on: https://skia-review.googlesource.com/67424
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
8 files changed