Plumb GrContext everywhere

There is no good way to split the monster CL up. This breaks out
the GrContext plumbing but doesn't use it.

Change-Id: I90856d428d372bcec3f8821e6364667b367927d4
Reviewed-on: https://skia-review.googlesource.com/133382
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/gn/gpu.gni b/gn/gpu.gni
index 65484c3..8cb6447 100644
--- a/gn/gpu.gni
+++ b/gn/gpu.gni
@@ -253,6 +253,7 @@
   "$_src/gpu/ops/GrAtlasTextOp.h",
   "$_src/gpu/ops/GrClearOp.cpp",
   "$_src/gpu/ops/GrClearOp.h",
+  "$_src/gpu/ops/GrClearStencilClipOp.cpp",
   "$_src/gpu/ops/GrClearStencilClipOp.h",
   "$_src/gpu/ops/GrCopySurfaceOp.cpp",
   "$_src/gpu/ops/GrCopySurfaceOp.h",