Use Skia's new simplified read/write pixels code paths

Bug: 826819
Change-Id: Ia6eaca75fe43f9d9ec94f8fe644a44e8e7436675
Reviewed-on: https://chromium-review.googlesource.com/1054520Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557943}

skia/config/SkUserConfig.h

@@ -220,11 +220,6 @@ SK_API void SkDebugf_FileLine(const char* file, int line, bool fatal,
 #define SK_SUPPORT_LEGACY_SVG_ARC_TO
 #endif
 
-// Remove after M66 branch to use new read/writePixels implementations
-#ifndef SK_LEGACY_GPU_PIXEL_OPS
-#define SK_LEGACY_GPU_PIXEL_OPS
-#endif
-
 #ifndef SK_SUPPORT_LEGACY_YUV_COLORSPACE
 #define SK_SUPPORT_LEGACY_YUV_COLORSPACE
 #endif