Don't compare coord change matrices to determine effect compatibility when using explicit local coords.

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/438053002
diff --git a/src/gpu/gl/GrGLProgramEffects.cpp b/src/gpu/gl/GrGLProgramEffects.cpp
index cff31e2..3fa4f15 100644
--- a/src/gpu/gl/GrGLProgramEffects.cpp
+++ b/src/gpu/gl/GrGLProgramEffects.cpp
@@ -90,8 +90,11 @@
 SkMatrix get_transform_matrix(const GrDrawEffect& drawEffect, int transformIdx) {
     const GrCoordTransform& coordTransform = drawEffect.effect()->coordTransform(transformIdx);
     SkMatrix combined;
-    if (kLocal_GrCoordSet == coordTransform.sourceCoords() &&
-        !drawEffect.programHasExplicitLocalCoords()) {
+
+    if (kLocal_GrCoordSet == coordTransform.sourceCoords()) {
+        // If we have explicit local coords then we shouldn't need a coord change.
+        SkASSERT(!drawEffect.programHasExplicitLocalCoords() ||
+                 drawEffect.getCoordChangeMatrix().isIdentity());
         combined.setConcat(coordTransform.getMatrix(), drawEffect.getCoordChangeMatrix());
     } else {
         combined = coordTransform.getMatrix();