Rename GrPipeline::Flags to GrPipeline::InputFlags

Renames the Flags to InputFlags and makes it a strongly typed enum.
Simplifies the relationship between GrSimpleMeshDrawOpHelper::Flags
and GrPipeline::InputFlags.

Bug: skia:
Change-Id: Ia25b8526ff96a47428dfbb82da18dbebdd382c5b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/204906
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/ops/GrAtlasTextOp.cpp b/src/gpu/ops/GrAtlasTextOp.cpp
index 1826a0b..7588c6c 100644
--- a/src/gpu/ops/GrAtlasTextOp.cpp
+++ b/src/gpu/ops/GrAtlasTextOp.cpp
@@ -390,9 +390,8 @@
 }
 
 void GrAtlasTextOp::onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) {
-    static const uint32_t kPipelineFlags = 0;
     flushState->executeDrawsAndUploadsForMeshDrawOp(
-            this, chainBounds, std::move(fProcessors), kPipelineFlags);
+            this, chainBounds, std::move(fProcessors), GrPipeline::InputFlags::kNone);
 }
 
 void GrAtlasTextOp::flush(GrMeshDrawOp::Target* target, FlushInfo* flushInfo) const {