Fix Collapse Button Focus Ring

Add Highlight Path for Collapse Button Focus

Bug: 922423
Test: Manual Test on PixelBook
Change-Id: If37e818714ccbd5248e2257e346378b3d848bbc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1542562
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649802}

ash/system/unified/collapse_button.cc

@@ -20,6 +20,7 @@
 #include "ui/views/animation/ink_drop_impl.h"
 #include "ui/views/animation/ink_drop_mask.h"
 #include "ui/views/border.h"
+#include "ui/views/view_class_properties.h"
 
 namespace ash {
 
@@ -104,6 +105,9 @@ void CustomShapeButton::PaintCustomShapePath(gfx::Canvas* canvas) {
 CollapseButton::CollapseButton(views::ButtonListener* listener)
     : CustomShapeButton(listener) {
   OnEnabledChanged();
+  auto path = std::make_unique<SkPath>(
+      CreateCustomShapePath(gfx::Rect(CalculatePreferredSize())));
+  SetProperty(views::kHighlightPathKey, path.release());
 }
 
 CollapseButton::~CollapseButton() = default;