ccpr: Clip quadratic hulls more efficiently

To minimize area, we should clip by the tangent line at maximum
height. Not mid-tangent. This is also easier to find.

Bug: skia:
Change-Id: I5099b62537f72e51e29bbced7998c0e588e287d9
Reviewed-on: https://skia-review.googlesource.com/119740
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
diff --git a/src/gpu/ccpr/GrCCCubicShader.cpp b/src/gpu/ccpr/GrCCCubicShader.cpp
index 4c9485e..f8a8352 100644
--- a/src/gpu/ccpr/GrCCCubicShader.cpp
+++ b/src/gpu/ccpr/GrCCCubicShader.cpp
@@ -14,7 +14,7 @@
 using Shader = GrCCCoverageProcessor::Shader;
 
 void GrCCCubicShader::emitSetupCode(GrGLSLVertexGeoBuilder* s, const char* pts,
-                                    const char* wind, const char** /*tighterHull*/) const {
+                                    const char* wind, const char** /*outHull4*/) const {
     // Define a function that normalizes the homogeneous coordinates T=t/s in order to avoid
     // exponent overflow.
     SkString normalizeHomogCoordFn;