[CrOS PhoneHub] Update A11y string for battery percent label.

ChromeVox will now verbalize "Phone Battery [displayed percent] percent"
instead of "[displayed percent]" without any context about what the
percent means.

Screenshot:
https://storage.cloud.google.com/chromium-translation-screenshots/72b4b1039e35fdd7f6d42bc25d509c1227e94d16

Fixed: 1152779
Change-Id: Icf6ccaf130989b8c73e12e6e47f760a987293bcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577756Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834509}

ash/ash_strings.grd

@@ -1066,6 +1066,9 @@ This file contains the strings for ash.
       <message name="IDS_ASH_PHONE_HUB_BATTERY_STATUS_CHARGING_USB" desc="The tooltip text indicating the phone is currently charging via a USB connection.">
         Charging via USB
       </message>
+      <message name="IDS_ASH_PHONE_HUB_BATTERY_PERCENTAGE_ACCESSIBLE_TEXT" desc="The accessible text of the phone battery percentage displayed in the Phone Hub tray.">
+        Phone battery <ph name="BATTERY_PERCENTAGE">$1<ex>100</ex></ph>%
+      </message>
       <message name="IDS_ASH_PHONE_HUB_BATTERY_SAVER_ON" desc="The tooltip text indicating the phone is currently in battery saver mode.">
         Battery saver mode is on
       </message>

ash/ash_strings_grd/IDS_ASH_PHONE_HUB_BATTERY_PERCENTAGE_ACCESSIBLE_TEXT.png.sha1

+72b4b1039e35fdd7f6d42bc25d509c1227e94d16
\ No newline at end of file

ash/system/phonehub/phone_status_view.cc

@@ -265,6 +265,9 @@ void PhoneStatusView::UpdateBatteryStatus() {
   SetBatteryTooltipText();
   battery_label_->SetText(
       base::FormatPercent(phone_status.battery_percentage()));
+  battery_label_->SetAccessibleName(l10n_util::GetStringFUTF16(
+      IDS_ASH_PHONE_HUB_BATTERY_PERCENTAGE_ACCESSIBLE_TEXT,
+      base::NumberToString16(phone_status.battery_percentage())));
 }
 
 PowerStatus::BatteryImageInfo PhoneStatusView::CalculateBatteryInfo() {

ui/views/controls/label.cc

@@ -108,6 +108,19 @@ void Label::SetText(const base::string16& new_text) {
   stored_selection_range_ = gfx::Range::InvalidRange();
 }
 
+void Label::SetAccessibleName(const base::string16& name) {
+  if (name == accessible_name_)
+    return;
+  accessible_name_ = name;
+  OnPropertyChanged(&accessible_name_, kPropertyEffectsNone);
+  NotifyAccessibilityEvent(ax::mojom::Event::kTextChanged, true);
+}
+
+const base::string16& Label::GetAccessibleName() const {
+  return accessible_name_.empty() ? full_text_->GetDisplayText()
+                                  : accessible_name_;
+}
+
 int Label::GetTextContext() const {
   return text_context_;
 }
@@ -619,7 +632,7 @@ void Label::GetAccessibleNodeData(ui::AXNodeData* node_data) {
   else
     node_data->role = ax::mojom::Role::kStaticText;
 
-  node_data->SetName(full_text_->GetDisplayText());
+  node_data->SetName(GetAccessibleName());
 }
 
 base::string16 Label::GetTooltipText(const gfx::Point& p) const {
@@ -1210,6 +1223,7 @@ ADD_PROPERTY_METADATA(base::string16, TooltipText)
 ADD_PROPERTY_METADATA(bool, HandlesTooltips)
 ADD_PROPERTY_METADATA(bool, CollapseWhenHidden)
 ADD_PROPERTY_METADATA(int, MaximumWidth)
+ADD_PROPERTY_METADATA(base::string16, AccessibleName)
 END_METADATA
 
 }  // namespace views

ui/views/controls/label.h

@@ -90,6 +90,12 @@ class VIEWS_EXPORT Label : public View,
   const base::string16& GetText() const;
   virtual void SetText(const base::string16& text);
 
+  // Set the accessibility name that will be announced by the screen reader.
+  // If this function is not called, the screen reader defaults to verbalizing
+  // the text value.
+  void SetAccessibleName(const base::string16& name);
+  const base::string16& GetAccessibleName() const;
+
   // Where the label appears in the UI. Passed in from the constructor. This is
   // a value from views::style::TextContext or an enum that extends it.
   int GetTextContext() const;
@@ -454,6 +460,9 @@ class VIEWS_EXPORT Label : public View,
 
   std::unique_ptr<SelectionController> selection_controller_;
 
+  // Accessibility data.
+  base::string16 accessible_name_;
+
   // Context menu related members.
   ui::SimpleMenuModel context_menu_contents_;
   std::unique_ptr<views::MenuRunner> context_menu_runner_;

ui/views/controls/label_unittest.cc

@@ -605,7 +605,9 @@ TEST_F(LabelTest, TooltipProperty) {
 }
 
 TEST_F(LabelTest, Accessibility) {
-  label()->SetText(ASCIIToUTF16("My special text."));
+  const base::string16 accessible_name = ASCIIToUTF16("A11y text.");
+
+  label()->SetText(ASCIIToUTF16("Displayed text."));
 
   ui::AXNodeData node_data;
   label()->GetAccessibleNodeData(&node_data);
@@ -614,6 +616,33 @@ TEST_F(LabelTest, Accessibility) {
             node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
   EXPECT_FALSE(
       node_data.HasIntAttribute(ax::mojom::IntAttribute::kRestriction));
+
+  // Setting a custom accessible name overrides the displayed text in
+  // screen reader announcements.
+  label()->SetAccessibleName(accessible_name);
+
+  label()->GetAccessibleNodeData(&node_data);
+  EXPECT_EQ(accessible_name,
+            node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
+  EXPECT_NE(label()->GetText(),
+            node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
+
+  // Changing the displayed text will not impact the non-empty accessible name.
+  label()->SetText(ASCIIToUTF16("Different displayed Text."));
+
+  label()->GetAccessibleNodeData(&node_data);
+  EXPECT_EQ(accessible_name,
+            node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
+  EXPECT_NE(label()->GetText(),
+            node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
+
+  // Clearing the accessible name will cause the screen reader to default to
+  // verbalizing the displayed text.
+  label()->SetAccessibleName(ASCIIToUTF16(""));
+
+  label()->GetAccessibleNodeData(&node_data);
+  EXPECT_EQ(label()->GetText(),
+            node_data.GetString16Attribute(ax::mojom::StringAttribute::kName));
 }
 
 TEST_F(LabelTest, TextChangeWithoutLayout) {