Add XP to handle the cases where we disable color write.
BUG=skia:
Review URL: https://codereview.chromium.org/787233003
diff --git a/src/gpu/GrProcessor.cpp b/src/gpu/GrProcessor.cpp
index 6699b52..75245f3 100644
--- a/src/gpu/GrProcessor.cpp
+++ b/src/gpu/GrProcessor.cpp
@@ -52,7 +52,7 @@
*/
static const int kFPFactoryCount = 37;
static const int kGPFactoryCount = 14;
-static const int kXPFactoryCount = 2;
+static const int kXPFactoryCount = 3;
template<>
void GrProcessorTestFactory<GrFragmentProcessor>::VerifyFactoryCount() {