Revert "Add color spin test for SkColorSpaceXformCanvas"

This reverts commit cb01aec63bcb3dee52afcf3605bcd64166b873c0.

Reason for revert: Breaks Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Debug-SK_USE_DISCARDABLE_SCALEDIMAGECACHE

Original change's description:
> Add color spin test for SkColorSpaceXformCanvas
> 
> Also changes behavior to treat nullptr srcs as sRGB.
> 
> Testing locally, it looks like 353 gms have no diffs from 8888.
> There are 269 diffs - some are fine (gms that do color space stuff)
> and some are bugs.
> 
> BUG=skia:
> 
> Change-Id: I55c2825f4f4b857e0b0a0ec050c6db82ac881492
> Reviewed-on: https://skia-review.googlesource.com/9738
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Matt Sarett <msarett@google.com>
> 

TBR=mtklein@google.com,msarett@google.com,brianosman@google.com,reviews@skia.org
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=skia:

Change-Id: I70bb69f747b863d267494e37a60888a51ab0184c
Reviewed-on: https://skia-review.googlesource.com/9823
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 99b0be1..2a83eaf 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -8,7 +8,6 @@
 #include "SkBitmap.h"
 #include "SkBitmapCache.h"
 #include "SkCanvas.h"
-#include "SkColorSpace_Base.h"
 #include "SkCrossContextImageData.h"
 #include "SkData.h"
 #include "SkImageEncoder.h"
@@ -319,9 +318,7 @@
         return nullptr;
     }
 
-    // Be sure to treat nullptr srcs as "equal to" sRGB.
-    if ((!this->colorSpace() && target->isSRGB()) ||
-            SkColorSpace_Base::EqualsIgnoreFlags(this->colorSpace(), target.get())) {
+    if (!this->colorSpace() || SkColorSpace::Equals(this->colorSpace(), target.get())) {
         return sk_ref_sp(const_cast<SkImage_Base*>(this));
     }