dark_mode: Correct wrong colors.

Bug: 1133063
Change-Id: I60db20876987e3bc9daebb377e0f6e254e7ccc24
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2439640Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Min Chen <minch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812761}

ash/style/ash_color_provider.cc

@@ -210,7 +210,7 @@ SkColor AshColorProvider::GetContentLayerColor(ContentLayerType type) const {
       return is_dark_mode ? gfx::kGoogleBlue300 : gfx::kGoogleBlue600;
     case ContentLayerType::kButtonLabelColorPrimary:
     case ContentLayerType::kButtonIconColorPrimary:
-      return is_dark_mode ? gfx::kGoogleGrey200 : gfx::kGoogleGrey900;
+      return is_dark_mode ? gfx::kGoogleGrey900 : gfx::kGoogleGrey200;
     case ContentLayerType::kSliderThumbColorDisabled:
       return is_dark_mode ? gfx::kGoogleGrey600 : gfx::kGoogleGrey600;
     case ContentLayerType::kSystemMenuIconColor: