Add accessibility support for stylus battery status

Bug: 1165451
Change-Id: I8095ef53ec141ef30bee22aec6930dc12b027637
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2623171
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842788}

ash/ash_strings.grd

@@ -1232,6 +1232,9 @@ This file contains the strings for ash.
       <message name="IDS_ASH_STYLUS_BATTERY_LOW_LABEL" desc="The label next to the stylus battery indicator when the battery level is below 24%">
         Low
       </message>
+      <message name="IDS_ASH_STYLUS_BATTERY_PERCENT_ACCESSIBLE" desc="The message used by accessibility to show stylus battery level.">
+        Stylus battery at <ph name="percentage">$1<ex>56</ex></ph> percent.
+      </message>
       <message name="IDS_ASH_STYLUS_TOOLS_CAPTURE_REGION_ACTION" desc="Title of the capture region action in the stylus tools (a pop-up panel next to the status tray). This causes a partial screenshot to be taken (the user selects an area of the screen to take a screenshot of).">
         Capture region
       </message>

ash/ash_strings_grd/IDS_ASH_STYLUS_BATTERY_PERCENT_ACCESSIBLE.png.sha1

+00c68e1647b1b8ce844dae493475be213cdbf8e3
\ No newline at end of file

ash/system/palette/palette_tray.cc

@@ -35,6 +35,8 @@
 #include "components/prefs/pref_change_registrar.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
+#include "ui/accessibility/ax_enums.mojom-shared.h"
+#include "ui/accessibility/ax_node_data.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/display/display.h"
@@ -91,10 +93,12 @@ bool ShouldShowOnDisplay(PaletteTray* palette_tray) {
 
 class BatteryView : public views::View {
  public:
-  explicit BatteryView(StylusBatteryDelegate* delegate) {
+  explicit BatteryView(StylusBatteryDelegate* delegate) : delegate_(delegate) {
     SetLayoutManager(std::make_unique<views::BoxLayout>(
         views::BoxLayout::Orientation::kHorizontal, gfx::Insets(), 4));
 
+    SetFocusBehavior(FocusBehavior::ACCESSIBLE_ONLY);
+
     icon_ = AddChildView(std::make_unique<views::ImageView>());
     icon_->SetImage(delegate->GetBatteryImage());
 
@@ -107,7 +111,15 @@ class BatteryView : public views::View {
     }
   }
 
+  void GetAccessibleNodeData(ui::AXNodeData* node_data) override {
+    node_data->role = ax::mojom::Role::kLabelText;
+    node_data->SetName(l10n_util::GetStringFUTF16(
+        IDS_ASH_STYLUS_BATTERY_PERCENT_ACCESSIBLE,
+        base::NumberToString16(delegate_->battery_level().value_or(0))));
+  }
+
  private:
+  StylusBatteryDelegate* const delegate_;
   views::ImageView* icon_ = nullptr;
   views::Label* label_ = nullptr;
 };