cbui: update fullscreen icon color

This change swaps the fullscreen icon color from #989898 to the enabled
menu item foreground color, which also fixes the contrast on this icon.
This makes the icon look a bit "heavy" in the menu but it's alright.

Bug: 957391
Change-Id: Idcc47784643def21d0841e0c93fd52fe2b54a27d
Ux-approved-by: monicagv
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816129Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699326}

chrome/browser/ui/views/toolbar/app_menu.cc

@@ -471,13 +471,12 @@ class AppMenu::ZoomView : public AppMenuView {
     // the keyboard navigation to work.
     DCHECK(Button::AsButton(fullscreen_button_));
 
-    // TODO(https://crbug.com/957391): Do away with this bespoke color. Ideally
-    // this should be kColorId_EnabledMenuItemForegroundColor. The color here is
-    // ripped directly from the old PNG asset for this image.
     fullscreen_button_->SetImage(
         ImageButton::STATE_NORMAL,
-        gfx::CreateVectorIcon(kFullscreenIcon,
-                              SkColorSetRGB(0x98, 0x98, 0x98)));
+        gfx::CreateVectorIcon(
+            kFullscreenIcon,
+            GetNativeTheme()->GetSystemColor(
+                ui::NativeTheme::kColorId_EnabledMenuItemForegroundColor)));
 
     // Since |fullscreen_button_| will reside in a menu, make it ALWAYS
     // focusable regardless of the platform.
@@ -548,7 +547,6 @@ class AppMenu::ZoomView : public AppMenuView {
     zoom_label_max_width_valid_ = false;
 
     ui::NativeTheme* theme = GetNativeTheme();
-    if (theme) {
     zoom_label_->SetEnabledColor(theme->GetSystemColor(
         ui::NativeTheme::kColorId_EnabledMenuItemForegroundColor));
     gfx::ImageSkia hovered_fullscreen_image = gfx::CreateVectorIcon(
@@ -560,7 +558,6 @@ class AppMenu::ZoomView : public AppMenuView {
     fullscreen_button_->SetImage(ImageButton::STATE_PRESSED,
                                  hovered_fullscreen_image);
   }
-  }
 
   // Overridden from ButtonListener.
   void ButtonPressed(views::Button* sender, const ui::Event& event) override {