Revert of GrFP can express distance vector field req., program builder declares variable for it

src/gpu/GrFragmentProcessor.cpp

Index: src/gpu/GrFragmentProcessor.cpp
diff --git a/src/gpu/GrFragmentProcessor.cpp b/src/gpu/GrFragmentProcessor.cpp
index a8a4898e78d99fd7baa3cafbde772f2fc49ac386..fdba610356c2dd74a0c786027809a29b0255f7a0 100644
--- a/src/gpu/GrFragmentProcessor.cpp
+++ b/src/gpu/GrFragmentProcessor.cpp
@@ -105,9 +105,6 @@
 
     if (child->usesLocalCoords()) {
         fUsesLocalCoords = true;
-    }
-    if (child->usesDistanceVectorField()) {
-        fUsesDistanceVectorField = true;
     }
 
     int index = fChildProcessors.count();