Move read swizzle from GL ConfigInfo to FormatInfo.

With this change I also removed GrPixelConfig as param to supportedReadPixelsColorType().
This meant some updates had to be made to Vulkan and Metal to make sure they return the
right GrColorType.

Bug: skia:6718
Change-Id: I71b6360489cf499692c7b777e5915090fad05c56
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/228349
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/GrSurfaceContext.cpp b/src/gpu/GrSurfaceContext.cpp
index 47a8940..1882e3c 100644
--- a/src/gpu/GrSurfaceContext.cpp
+++ b/src/gpu/GrSurfaceContext.cpp
@@ -172,8 +172,7 @@
     bool flip = srcProxy->origin() == kBottomLeft_GrSurfaceOrigin;
 
     auto supportedRead = caps->supportedReadPixelsColorType(
-            this->colorSpaceInfo().colorType(), srcProxy->config(), srcProxy->backendFormat(),
-            dstInfo.colorType());
+            this->colorSpaceInfo().colorType(), srcProxy->backendFormat(), dstInfo.colorType());
 
     bool makeTight = !caps->readPixelsRowBytesSupport() && tightRowBytes != rowBytes;