Polish holding space images in item chip views.

Addresses two problems:
1. Rendered thumbnails may not have opaque backgrounds which can make
   them look a bit untidy when shown in holding space chip item views.
2. Generic file type icons lack sufficient contrast in some contexts in
   which they are shown (e.g. bubble, shelf preview, etc.).

UX solution:
1. Add white background to holding space images in item chip views.
2. Darken generic file type icons.
3. Revisit later w/ dark/light mode effort.

Bug: 1163702
Change-Id: I32ffea29014073e2e0eac74d3db7635e9071b3c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2616752Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Commit-Queue: David Black <dmblack@google.com>
Cr-Commit-Position: refs/heads/master@{#841289}

ash/system/holding_space/holding_space_color_provider_impl.cc

@@ -5,6 +5,7 @@
 #include "ash/system/holding_space/holding_space_color_provider_impl.h"
 
 #include "ash/style/ash_color_provider.h"
+#include "ui/gfx/color_palette.h"
 
 namespace ash {
 
@@ -18,8 +19,7 @@ SkColor HoldingSpaceColorProviderImpl::GetBackgroundColor() const {
 }
 
 SkColor HoldingSpaceColorProviderImpl::GetFileIconColor() const {
-  return AshColorProvider::Get()->GetContentLayerColor(
-      AshColorProvider::ContentLayerType::kIconColorPrimary);
+  return gfx::kGoogleGrey700;
 }
 
 }  // namespace ash

ash/system/holding_space/holding_space_item_chip_view.cc

@@ -12,6 +12,7 @@
 #include "ash/system/holding_space/holding_space_util.h"
 #include "ui/compositor/paint_recorder.h"
 #include "ui/gfx/skia_paint_util.h"
+#include "ui/views/background.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/layout/fill_layout.h"
@@ -87,6 +88,15 @@ HoldingSpaceItemChipView::HoldingSpaceItemChipView(
 
   image_ = AddChildView(std::make_unique<RoundedImageView>(
       kHoldingSpaceChipIconSize / 2, RoundedImageView::Alignment::kLeading));
+  image_->SetBackground(views::CreateRoundedRectBackground(
+      SK_ColorWHITE, kHoldingSpaceChipIconSize / 2));
+
+  // Subscribe to be notified of changes to `item_`'s image.
+  image_subscription_ =
+      item->image().AddImageSkiaChangedCallback(base::BindRepeating(
+          &HoldingSpaceItemChipView::UpdateImage, base::Unretained(this)));
+
+  UpdateImage();
 
   label_and_pin_button_container_ =
       AddChildView(std::make_unique<views::View>());
@@ -107,13 +117,6 @@ HoldingSpaceItemChipView::HoldingSpaceItemChipView(
   label_->layer()->SetFillsBoundsOpaquely(false);
   label_->layer()->SetMaskLayer(label_mask_layer_owner_->layer());
 
-  // Subscribe to be notified of changes to `item_`'s image.
-  image_subscription_ =
-      item->image().AddImageSkiaChangedCallback(base::BindRepeating(
-          &HoldingSpaceItemChipView::UpdateImage, base::Unretained(this)));
-
-  UpdateImage();
-
   views::View* pin_button_container =
       label_and_pin_button_container_->AddChildView(
           std::make_unique<views::View>());