dark_mode: Remove kNotificationCenterCollapseIcon.

Collapse button use kUnifiedMenuExpandIcon now, remove the old one. And
update the function name from OnEnabledChanged to UpdateVectorIcon.

Bug: 1131543
Change-Id: I5d42a7941b07255da1ccc267bc5b44934dc4f492
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2486661
Commit-Queue: Min Chen <minch@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819927}

ash/resources/vector_icons/BUILD.gn

@@ -110,7 +110,6 @@ aggregate_vector_icons2("ash_vector_icons") {
     "notification_capslock.icon",
     "notification_center_all_done.icon",
     "notification_center_clear_all.icon",
-    "notification_center_collapse.icon",
     "notification_center_do_not_disturb_off.icon",
     "notification_center_do_not_disturb_on.icon",
     "notification_center_empty.icon",

ash/resources/vector_icons/notification_center_collapse.icon

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-CANVAS_DIMENSIONS, 40,
-MOVE_TO, 10.82f, 12,
-LINE_TO, 20, 21.89f,
-LINE_TO, 29.18f, 12,
-LINE_TO, 32, 15.05f,
-LINE_TO, 20, 28,
-LINE_TO, 8, 15.05f,
-CLOSE

ash/system/unified/collapse_button.cc

@@ -16,7 +16,7 @@ namespace ash {
 
 CollapseButton::CollapseButton(views::ButtonListener* listener)
     : CustomShapeButton(listener) {
-  OnEnabledChanged();
+  UpdateVectorIcon();
 }
 
 CollapseButton::~CollapseButton() = default;
@@ -58,7 +58,7 @@ const char* CollapseButton::GetClassName() const {
   return "CollapseButton";
 }
 
-void CollapseButton::OnEnabledChanged() {
+void CollapseButton::UpdateVectorIcon() {
   const SkColor icon_color = AshColorProvider::Get()->GetContentLayerColor(
       AshColorProvider::ContentLayerType::kIconColorPrimary);
   SetImage(views::Button::STATE_NORMAL,

ash/system/unified/collapse_button.h

@@ -29,12 +29,15 @@ class CollapseButton : public CustomShapeButton {
   const char* GetClassName() const override;
 
  private:
-  void OnEnabledChanged();
+  // Update the vector icon on initializing CollapseButton or when the |Enabled|
+  // property of CollapseButton changes. The vector icon will have different
+  // colors on the |Enabled| property.
+  void UpdateVectorIcon();
 
   double expanded_amount_ = 1.0;
   views::PropertyChangedSubscription enabled_changed_subscription_ =
       AddEnabledChangedCallback(
-          base::BindRepeating(&CollapseButton::OnEnabledChanged,
+          base::BindRepeating(&CollapseButton::UpdateVectorIcon,
                               base::Unretained(this)));
 
   DISALLOW_COPY_AND_ASSIGN(CollapseButton);