io_surface: Conditionalize SRGB colorspace coercion with flag.

This change adds a default-on flag controlling the coercion of
REC709 to SRGB added in crrev/c/2550554.

Bug: 1151957, b:173124811
Change-Id: I39d91c2cd5fc047e8a67c649a862753fe8daa47b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2556962
Commit-Queue: Markus Handell <handellm@google.com>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830935}

ui/gfx/mac/io_surface.cc

@@ -10,6 +10,7 @@
 #include <stdint.h>
 
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/mach_logging.h"
@@ -24,6 +25,9 @@ namespace gfx {
 
 namespace {
 
+const base::Feature kIOSurfaceUseNamedSRGBForREC709{
+    "IOSurfaceUseNamedSRGBForREC709", base::FEATURE_ENABLED_BY_DEFAULT};
+
 void AddIntegerValue(CFMutableDictionaryRef dictionary,
                      const CFStringRef key,
                      int32_t value) {
@@ -135,7 +139,8 @@ bool IOSurfaceSetColorSpace(IOSurfaceRef io_surface,
   CFStringRef color_space_name = nullptr;
   if (__builtin_available(macos 10.12, *)) {
     if (color_space == ColorSpace::CreateSRGB() ||
-        color_space == ColorSpace::CreateREC709()) {
+        (base::FeatureList::IsEnabled(kIOSurfaceUseNamedSRGBForREC709) &&
+         color_space == ColorSpace::CreateREC709())) {
       color_space_name = kCGColorSpaceSRGB;
     } else if (color_space == ColorSpace::CreateDisplayP3D65()) {
       color_space_name = kCGColorSpaceDisplayP3;