Remove GP from drawstate, revision of invariant output for GP

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/c6bc58eded89b0c0a36b8e20e193c200f297a0da

Review URL: https://codereview.chromium.org/791743003
diff --git a/src/gpu/effects/GrConvexPolyEffect.cpp b/src/gpu/effects/GrConvexPolyEffect.cpp
index 248cd17..1430716 100644
--- a/src/gpu/effects/GrConvexPolyEffect.cpp
+++ b/src/gpu/effects/GrConvexPolyEffect.cpp
@@ -44,9 +44,9 @@
     virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const SK_OVERRIDE {
         if (fRect.isEmpty()) {
             // An empty rect will have no coverage anywhere.
-            inout->mulByKnownAlpha(0);
+            inout->mulByKnownSingleComponent(0);
         } else {
-            inout->mulByUnknownAlpha();
+            inout->mulByUnknownSingleComponent();
         }
     }
 
@@ -323,7 +323,7 @@
 GrConvexPolyEffect::~GrConvexPolyEffect() {}
 
 void GrConvexPolyEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
-    inout->mulByUnknownAlpha();
+    inout->mulByUnknownSingleComponent();
 }
 
 void GrConvexPolyEffect::getGLProcessorKey(const GrGLCaps& caps,