Rename outputSwizzle->writeSwizzle.

It is also used for writes to surfaces other than fragment shader
output. e.g. clears.

Change-Id: Id1eb79be6d1a8aed936456bffa59dee32661cec8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/280344
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/glsl/GrGLSLProgramBuilder.cpp b/src/gpu/glsl/GrGLSLProgramBuilder.cpp
index a427be5..fba5b3d 100644
--- a/src/gpu/glsl/GrGLSLProgramBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLProgramBuilder.cpp
@@ -255,7 +255,7 @@
                                        fFS.getSecondaryColorOutputName(),
                                        dstTextureSamplerHandle,
                                        dstTextureOrigin,
-                                       this->pipeline().outputSwizzle());
+                                       this->pipeline().writeSwizzle());
     fXferProcessor->emitCode(args);
 
     // We have to check that effects and the code they emit are consistent, ie if an effect