Create swizzle table inside of glsl caps

include/gpu/GrContextOptions.h

Index: include/gpu/GrContextOptions.h
diff --git a/include/gpu/GrContextOptions.h b/include/gpu/GrContextOptions.h
index 4b70105559fa1a9dcdadfae486be4497d7eed6ed..ef6e38031d5e486a444bd111b96b8ed6777da35e 100644
--- a/include/gpu/GrContextOptions.h
+++ b/include/gpu/GrContextOptions.h
@@ -18,7 +18,8 @@ struct GrContextOptions {
         , fSuppressDualSourceBlending(false)
         , fGeometryBufferMapThreshold(-1)
         , fUseDrawInsteadOfPartialRenderTargetWrite(false)
-        , fImmediateMode(false) {}
+        , fImmediateMode(false)
+        , fUseShaderSwizzling(false) {}
 
     // EXPERIMENTAL
     // May be removed in the future, or may become standard depending
@@ -46,6 +47,10 @@ struct GrContextOptions {
     /** The GrContext operates in immedidate mode. It will issue all draws to the backend API
         immediately. Intended to ease debugging. */
     bool fImmediateMode;
+
+    /** Force us to do all swizzling manually in the shader and don't rely on extensions to do
+        swizzling. */
+    bool fUseShaderSwizzling;
 };
 
 #endif