Perform color correction on png decodes

src/opts/SkOpts_sse41.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOpts.h"
 
 #define SK_OPTS_NS sse41
 #include "SkBlurImageFilter_opts.h"
 #include "SkBlitRow_opts.h"
 #include "SkBlend_opts.h"
 #include "SkColorXform_opts.h"
 
 namespace SkOpts {
     void Init_sse41() {
         box_blur_xx          = sse41::box_blur_xx;
         box_blur_xy          = sse41::box_blur_xy;
         box_blur_yx          = sse41::box_blur_yx;
         srcover_srgb_srgb    = sse41::srcover_srgb_srgb;
         blit_row_s32a_opaque = sse41::blit_row_s32a_opaque;
 
-        color_xform_RGB1_to_2dot2        = sse41::color_xform_RGB1_to_2dot2;
-        color_xform_RGB1_to_srgb         = sse41::color_xform_RGB1_to_srgb;
-        color_xform_RGB1_to_table        = sse41::color_xform_RGB1_to_table;
-        color_xform_RGB1_to_linear       = sse41::color_xform_RGB1_to_linear;
-        color_xform_RGB1_to_2dot2_swaprb = sse41::color_xform_RGB1_to_2dot2_swaprb;
-        color_xform_RGB1_to_srgb_swaprb  = sse41::color_xform_RGB1_to_srgb_swaprb;
-        color_xform_RGB1_to_table_swaprb = sse41::color_xform_RGB1_to_table_swaprb;
+        color_xform_RGB1_to_2dot2               = sse41::color_xform_RGB1_to_2dot2;

[mtklein, 2016/07/28 19:35:12]

So, all 14 of these routines are really going to be hot?

[msarett, 2016/07/28 20:39:04]

I think these 6 are critical.
RGBA->RGBA          (sRGB)
RGBA->BGRA          (sRGB)
RGBA->RGBA (Premul) (sRGB)
RGBA->BGRA (Premul) (sRGB)
RGBA->Half
RGBA->Half (Premul) 

The 4 to2Dot2 routines are not so critical.  Looks like only 5% of Dsts are
2Dot2 (and we may end up treating these as sRGB anyway).

The 4 toTable routine are also not so critical.  They exist because we need a
"catch all" until I can convince the UMA that all Dsts are sRGB.

I don't feel too strongly about how we should implement these last 8 routines. 
The way they are written now is convenient because they share code with the
critical routines, but I'm opened to other ideas.

Actually, I really, really want to delete the toTable routines.  But I think
that depends on me figuring out what's going on with the 11% "nonstandard" Dst
profiles.

[msarett, 2016/07/29 18:23:01]

I wrote a CL that removes the special case for 2Dot2.
https://codereview.chromium.org/2189193002/

Haven't published it yet because I'm not sure about it...  It removes a lot of
code but is more than 2x slower and is less correct.  It's definitely an option
though as it becomes necessary to keep this sane.

[mtklein, 2016/07/29 18:48:56]

Seems like we want to keep all 14 for now.

[msarett, 2016/07/29 20:07:50]

Acknowledged.

+        color_xform_RGB1_to_srgb                = sse41::color_xform_RGB1_to_srgb;
+        color_xform_RGB1_to_table               = sse41::color_xform_RGB1_to_table;
+        color_xform_RGB1_to_linear              = sse41::color_xform_RGB1_to_linear;
+        color_xform_RGB1_to_2dot2_swaprb        = sse41::color_xform_RGB1_to_2dot2_swaprb;
+        color_xform_RGB1_to_srgb_swaprb         = sse41::color_xform_RGB1_to_srgb_swaprb;
+        color_xform_RGB1_to_table_swaprb        = sse41::color_xform_RGB1_to_table_swaprb;
+        color_xform_RGB1_to_2dot2_premul        = sse41::color_xform_RGB1_to_2dot2_premul;
+        color_xform_RGB1_to_srgb_premul         = sse41::color_xform_RGB1_to_srgb_premul;
+        color_xform_RGB1_to_table_premul        = sse41::color_xform_RGB1_to_table_premul;
+        color_xform_RGB1_to_linear_premul       = sse41::color_xform_RGB1_to_linear_premul;
+        color_xform_RGB1_to_2dot2_premul_swaprb = sse41::color_xform_RGB1_to_2dot2_premul_swaprb;
+        color_xform_RGB1_to_srgb_premul_swaprb  = sse41::color_xform_RGB1_to_srgb_premul_swaprb;
+        color_xform_RGB1_to_table_premul_swaprb = sse41::color_xform_RGB1_to_table_premul_swaprb;
     }
 }