hide/remove obsolete/tricky SkMatrix methods

Change-Id: Iee399b929e8ca1a7326a326a643539d05e333d81
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260818
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/src/gpu/glsl/GrGLSLGeometryProcessor.cpp b/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
index 26288b9..6e8b0d7 100644
--- a/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
@@ -119,7 +119,7 @@
             } else {
                 m = GetTransformMatrix(transform, SkMatrix::I());
             }
-            if (!fInstalledTransforms[i].fCurrentValue.cheapEqualTo(m)) {
+            if (!SkMatrixPriv::CheapEqual(fInstalledTransforms[i].fCurrentValue, m)) {
                 pdman.setSkMatrix(fInstalledTransforms[i].fHandle.toIndex(), m);
                 fInstalledTransforms[i].fCurrentValue = m;
             }