AshColorProvider: Add button icon color variant.

Bug: 972162
Change-Id: I64027b7ba3be9842b4e8c4e7a270e9ae96d78cc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2290290Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786886}

ash/style/ash_color_provider.cc

@@ -297,10 +297,12 @@ SkColor AshColorProvider::GetContentLayerColorImpl(
       return cros_colors::ResolveColor(ColorName::kDefaultIconColorProminent,
                                        color_mode);
     case ContentLayerType::kButtonLabelColor:
+    case ContentLayerType::kButtonIconColor:
       light_color = gfx::kGoogleGrey700;
       dark_color = gfx::kGoogleGrey200;
       break;
     case ContentLayerType::kButtonLabelColorPrimary:
+    case ContentLayerType::kButtonIconColorPrimary:
       light_color = gfx::kGoogleRed900;
       dark_color = gfx::kGoogleRed200;
       break;

ash/style/ash_color_provider.h

@@ -100,6 +100,9 @@ class ASH_EXPORT AshColorProvider {
     kButtonLabelColor,
     kButtonLabelColorPrimary,
 
+    kButtonIconColor,
+    kButtonIconColorPrimary,
+
     // Color for system menu icon buttons with inverted dark mode colors, e.g,
     // FeaturePodIconButton
     kSystemMenuIconColor,