Move glsl onto EmitArgs struct for emitCode

BUG=skia:

Review URL: https://codereview.chromium.org/1453623003
diff --git a/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp b/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
index 4633bc2..31ceda4 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
@@ -272,6 +272,7 @@
     fragBuilder->codeAppend("\t");
     this->emitColor(args.fBuilder,
                     fragBuilder,
+                    args.fGLSLCaps,
                     ge,
                     tName.c_str(),
                     args.fOutputColor,
@@ -544,6 +545,7 @@
     fragBuilder->codeAppend("\t\t");
     this->emitColor(args.fBuilder,
                     fragBuilder,
+                    args.fGLSLCaps,
                     ge,
                     tName.c_str(),
                     args.fOutputColor,
@@ -733,6 +735,7 @@
 
     this->emitColor(args.fBuilder,
                     fragBuilder,
+                    args.fGLSLCaps,
                     ge,
                     tName.c_str(),
                     args.fOutputColor,
@@ -998,6 +1001,7 @@
 
     this->emitColor(args.fBuilder,
                     fragBuilder,
+                    args.fGLSLCaps,
                     ge,
                     tName.c_str(),
                     args.fOutputColor,
@@ -1248,6 +1252,7 @@
     fragBuilder->codeAppend("\t\t");
     this->emitColor(args.fBuilder,
                     fragBuilder,
+                    args.fGLSLCaps,
                     ge,
                     tName.c_str(),
                     args.fOutputColor,