Create swizzle table inside of glsl caps

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/4036674952f341dab0695c3b054fefa5bb8cdec1

Review URL: https://codereview.chromium.org/1420033005
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index 75cecdf..22f6a6d 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -77,6 +77,7 @@
 
 void GrShaderCaps::applyOptionsOverrides(const GrContextOptions& options) {
     fDualSourceBlendingSupport = fDualSourceBlendingSupport && !options.fSuppressDualSourceBlending;
+    this->onApplyOptionsOverrides(options);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -127,6 +128,7 @@
     } else {
         fMaxTileSize = options.fMaxTileSizeOverride;
     }
+    this->onApplyOptionsOverrides(options);
 }
 
 static SkString map_flags_to_string(uint32_t flags) {