Rename GrCaps textureSwizzle to readSwizzle.

Change-Id: Ia5e2c4d3ca7346a1ad7559cd158ed632a70145bc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260699
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/mtl/GrMtlCaps.h b/src/gpu/mtl/GrMtlCaps.h
index fa2de1c..6b830d6 100644
--- a/src/gpu/mtl/GrMtlCaps.h
+++ b/src/gpu/mtl/GrMtlCaps.h
@@ -86,7 +86,7 @@
         return fColorTypeToFormatTable[idx];
     }
 
-    GrSwizzle getTextureSwizzle(const GrBackendFormat&, GrColorType) const override;
+    GrSwizzle getReadSwizzle(const GrBackendFormat&, GrColorType) const override;
     GrSwizzle getOutputSwizzle(const GrBackendFormat&, GrColorType) const override;
 
     GrProgramDesc makeDesc(const GrRenderTarget*, const GrProgramInfo&) const override;
@@ -127,7 +127,7 @@
         };
         uint32_t fFlags = 0;
 
-        GrSwizzle fTextureSwizzle;
+        GrSwizzle fReadSwizzle;
         GrSwizzle fOutputSwizzle;
     };