Remove sk_OutColor built-in variable.

Change-Id: I41a5aea7b01efe8901498621197b9a5ff0f4fe5f
Bug: skia:10549
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/344656
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
diff --git a/tests/ProgramsTest.cpp b/tests/ProgramsTest.cpp
index 1963c0a..d4e3335 100644
--- a/tests/ProgramsTest.cpp
+++ b/tests/ProgramsTest.cpp
@@ -42,7 +42,7 @@
 class GLBigKeyProcessor : public GrGLSLFragmentProcessor {
 public:
     void emitCode(EmitArgs& args) override {
-        args.fFragBuilder->codeAppendf("%s = half4(1);\n", args.fOutputColor);
+        args.fFragBuilder->codeAppendf("return half4(1);\n");
     }
 
     static void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder* b) {
@@ -63,6 +63,8 @@
 
     const char* name() const override { return "Big_Ole_Key"; }
 
+    bool usesExplicitReturn() const override { return true; }
+
     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         return new GLBigKeyProcessor;
     }
@@ -99,6 +101,8 @@
 
     const char* name() const override { return "Block_Input"; }
 
+    bool usesExplicitReturn() const override { return true; }
+
     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new GLFP; }
 
     std::unique_ptr<GrFragmentProcessor> clone() const override {
@@ -110,7 +114,7 @@
     public:
         void emitCode(EmitArgs& args) override {
             SkString temp = this->invokeChild(0, args);
-            args.fFragBuilder->codeAppendf("%s = %s;", args.fOutputColor, temp.c_str());
+            args.fFragBuilder->codeAppendf("return %s;", temp.c_str());
         }
 
     private: