Revert "Add function to GrDataUtils to handle color conversions."

This reverts commit 55091020435c876d12f2d74697b21edbc98e13fa.

Reason for revert: valgrind issues

Original change's description:
> Add function to GrDataUtils to handle color conversions.
> 
> Like SkConvertPixels but knows about all GrColorTypes, origin, and can
> apply an arbitrary GrSwizzle.
> 
> Use in GrSurfaceContext read/write pixels methods.
> 
> Add support for '0' to GrSwizzle.
> 
> 
> Change-Id: Ib9dd215fcb0ee8b33c4020893c22b4ab7ce1f40b
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/220761
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,brianosman@google.com

Change-Id: If50f3e26875787d9309009e9c701774fbad0afda
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/221538
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrSwizzle.cpp b/src/gpu/GrSwizzle.cpp
index 138b24f..21fe834 100644
--- a/src/gpu/GrSwizzle.cpp
+++ b/src/gpu/GrSwizzle.cpp
@@ -11,17 +11,11 @@
 void GrSwizzle::apply(SkRasterPipeline* pipeline) const {
     SkASSERT(pipeline);
     switch (fKey) {
-        case GrSwizzle("rgba").asKey():
+        case GrSwizzle::RGBA().asKey():
             return;
-        case GrSwizzle("bgra").asKey():
+        case GrSwizzle::BGRA().asKey():
             pipeline->append(SkRasterPipeline::swap_rb);
             return;
-        case GrSwizzle("aaa1").asKey():
-            pipeline->append(SkRasterPipeline::alpha_to_gray);
-            return;
-        case GrSwizzle("rgb1").asKey():
-            pipeline->append(SkRasterPipeline::force_opaque);
-            return;
         default: {
             GR_STATIC_ASSERT(sizeof(uintptr_t) >= 4 * sizeof(char));
             // Rather than allocate the 4 control bytes on the heap somewhere, just jam them right