desks: Change ARGB color of desks bar to 0xBC202124

I claim that Issue 988524 is fully addressed just by changing the ARGB
color. The desks bar appears only in overview mode, wherein the whole
wallpaper is blurred. As the goal in the first place is to be consistent
with the shelf, the desks bar shall add no additional blur. The issue
mentions using kTransparentWithBlur, but that would be inappropriate.

Test: manual
Bug: 988524
Change-Id: I3d432b73bd4e35809db304f95001a7de17ef7f81
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730768Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683350}

ash/wm/desks/desks_bar_view.cc

@@ -22,6 +22,7 @@
 #include "ui/aura/window.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/events/event_observer.h"
+#include "ui/gfx/color_palette.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/views/event_monitor.h"
 #include "ui/views/widget/widget.h"
@@ -33,6 +34,9 @@ namespace {
 
 constexpr int kBarHeight = 104;
 
+// TODO(minch): Migrate this to retrieve the color from AshColorProvider.
+constexpr SkColor kBarColor = SkColorSetA(gfx::kGoogleGrey900, 0xBC);  // 74%
+
 base::string16 GetMiniViewTitle(int mini_view_index) {
   DCHECK_GE(mini_view_index, 0);
   DCHECK_LT(mini_view_index, 4);
@@ -117,7 +121,7 @@ DesksBarView::DesksBarView()
 
   background_view_->SetPaintToLayer(ui::LAYER_SOLID_COLOR);
   background_view_->layer()->SetFillsBoundsOpaquely(false);
-  background_view_->layer()->SetColor(SkColorSetARGB(60, 0, 0, 0));
+  background_view_->layer()->SetColor(kBarColor);
 
   AddChildView(background_view_);
   AddChildView(new_desk_button_);