color: Ensure solid color IOSurface layers are sRGB

ui/gfx/BUILD.gn

Index: ui/gfx/BUILD.gn
diff --git a/ui/gfx/BUILD.gn b/ui/gfx/BUILD.gn
index 89bcfbe020b448e37547770102e11fd84669799c..3e8949d83c289b7cdeed83e57f9f766dc1987974 100644
--- a/ui/gfx/BUILD.gn
+++ b/ui/gfx/BUILD.gn
@@ -163,8 +163,6 @@ component("gfx") {
     "shadow_value.h",
     "skbitmap_operations.cc",
     "skbitmap_operations.h",
-    "switches.cc",
-    "switches.h",
     "sys_color_change_listener.cc",
     "sys_color_change_listener.h",
     "text_constants.h",
@@ -241,6 +239,7 @@ component("gfx") {
     ":memory_buffer_sources",
     ":native_widget_types",
     ":selection_bound_sources",
+    ":switches_sources",
     "//base",
     "//skia",
     "//third_party/icu",
@@ -529,6 +528,7 @@ source_set("memory_buffer_sources") {
 
   deps = [
     ":native_widget_types",
+    ":switches_sources",
     "//base",
     "//ui/gfx/geometry",
   ]
@@ -545,6 +545,22 @@ source_set("memory_buffer_sources") {
   }
 }
 
+source_set("switches_sources") {
+  visibility = [ ":*" ]  # Depend on through ":switches_sources".
+
+  sources = [
+    "switches.cc",
+    "switches.h",

[Nico, 2017/05/09 21:41:11]

These aren't generated or anything -- is the motivation to effectively do

  public = [ "switches.h" ]

over in gfx? (see `gn help public`)

(and possibly for a few more headers)

[ccameron, 2017/05/10 10:19:31]

I don't think so.

The motivation was because
- I need to access switches.h in mac/io_surface.cc, which is part of
memory_buffer_sources
- gfx depends on memory_buffer_sources.
- switches.h is in gfx

So, trying to include switches.h results in the circular dependency
memory_buffer_sources (mac/io_surface.cc) -> gfx (switches.h) ->
memory_buffer_sources

So, to break the dependency, I took switches.h and moved it to its own target.

+  ]
+
+  defines = [ "GFX_IMPLEMENTATION" ]
+
+  deps = [
+    ":gfx_export",
+    "//base",
+  ]
+}
+
 static_library("test_support") {
   testonly = true
   sources = [