Fix label colors for dark native themes (incognito, shelf).

ui/native_theme/native_theme_dark_aura.cc

Index: ui/native_theme/native_theme_dark_aura.cc
diff --git a/ui/native_theme/native_theme_dark_aura.cc b/ui/native_theme/native_theme_dark_aura.cc
index d0d92739e5e7bd06a00192d907e16c64d116fb9b..f40f64c654bd48061b9941c4b791d450a093a2c8 100644
--- a/ui/native_theme/native_theme_dark_aura.cc
+++ b/ui/native_theme/native_theme_dark_aura.cc
@@ -31,6 +31,12 @@ SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
       SkColorSetA(kResultsTableText, 0x80);
 
   switch (color_id) {
+    // Window

[tdanderson, 2016/10/06 14:05:05]

Comparing this change to the CL where the regression was caused, I'm not 100%
certain why this fixes the label colors. Can you please clarify?

[Evan Stade, 2016/10/06 15:35:46]

we used to have a label background color for dark themes which was dark. This
color was being used for auto color readability. Then that got removed and we
started using dialog bg color in its place. That was returning red. Auto color
readability code decided that black on red was better than white on red.

+    case kColorId_WindowBackground:
+    case kColorId_DialogBackground:
+    case kColorId_BubbleBackground:
+      return SK_ColorBLACK;
+
     // Button
     case kColorId_ButtonEnabledColor:
       return kButtonEnabledColor;
@@ -91,9 +97,6 @@ SkColor NativeThemeDarkAura::GetSystemColor(ColorId color_id) const {
       return NativeThemeAura::GetSystemColor(color_id);
 
     // Any other color is not defined and shouldn't be used in a dark theme.
-    case kColorId_WindowBackground:
-    case kColorId_DialogBackground:
-    case kColorId_BubbleBackground:
     case kColorId_UnfocusedBorderColor:
     case kColorId_ButtonDisabledColor:
     case kColorId_ButtonHoverColor: