Move GrFixedClip into src directory

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2254343003

Review-Url: https://codereview.chromium.org/2254343003
diff --git a/gm/texdata.cpp b/gm/texdata.cpp
index 4cad113..0c23749 100644
--- a/gm/texdata.cpp
+++ b/gm/texdata.cpp
@@ -12,6 +12,7 @@
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "GrDrawContext.h"
+#include "GrFixedClip.h"
 #include "SkColorPriv.h"
 #include "effects/GrPorterDuffXferProcessor.h"
 #include "effects/GrSimpleTextureEffect.h"