[Live Caption] Refactor caption bubble accessibility.

Rather than override the caption bubble's view accessibility with
virtual children, override the label's view accessibility with a
different AXNode per line. This allows us to take advantage of the
views' visibility and bounds--whereas previously we needed to keep track
of whether the error was visible or not.

This CL also renames functions and variables from virtual_children to
ax_lines. It sets the label role to be kParagraph and each ax_line role
to be kStaticText.

Bug: 1055150
Change-Id: Ic70187b1e0159d4fa012bc44e1ec40b2357717e8
AX-Relnotes: N/A (Feature has not launched)
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2602660Reviewed-by: Josiah Krutz <josiahk@google.com>
Commit-Queue: Abigail Klein <abigailbklein@google.com>
Cr-Commit-Position: refs/heads/master@{#839778}

chrome/browser/ui/views/accessibility/caption_bubble.cc

@@ -193,6 +193,85 @@ class CaptionBubbleFrameView : public views::BubbleFrameView {
 BEGIN_METADATA(CaptionBubbleFrameView, views::BubbleFrameView)
 END_METADATA
 
+class CaptionBubbleLabel : public views::Label {
+ public:
+  METADATA_HEADER(CaptionBubbleLabel);
+  CaptionBubbleLabel() = default;
+  ~CaptionBubbleLabel() override = default;
+  CaptionBubbleLabel(const CaptionBubbleLabel&) = delete;
+  CaptionBubbleLabel& operator=(const CaptionBubbleLabel&) = delete;
+
+  void GetAccessibleNodeData(ui::AXNodeData* node_data) override {
+    node_data->role = ax::mojom::Role::kParagraph;
+  }
+
+  void SetText(const base::string16& text) override {
+    views::Label::SetText(text);
+
+    // Only update ViewAccessibility if accessibility is enabled.
+    if (content::BrowserAccessibilityState::GetInstance()
+            ->GetAccessibilityMode()
+            .is_mode_off()) {
+      return;
+    }
+
+    auto& ax_lines = GetViewAccessibility().virtual_children();
+    if (text.empty() && !ax_lines.empty()) {
+      GetViewAccessibility().RemoveAllVirtualChildViews();
+      return;
+    }
+
+    const size_t num_lines = GetRequiredLines();
+    size_t start = 0;
+    for (size_t i = 0; i < num_lines - 1; ++i) {
+      size_t end = GetTextIndexOfLine(i + 1);
+      base::string16 substring = text.substr(start, end - start);
+      UpdateAXLine(substring, i, gfx::Range(start, end));
+      start = end;
+    }
+    base::string16 substring = text.substr(start, text.size() - start);
+    if (!substring.empty()) {
+      UpdateAXLine(substring, num_lines - 1, gfx::Range(start, text.size()));
+    }
+
+    // Remove all ax_lines that don't have a corresponding line.
+    size_t num_ax_lines = ax_lines.size();
+    for (size_t i = num_lines; i < num_ax_lines; ++i) {
+      GetViewAccessibility().RemoveVirtualChildView(ax_lines.back().get());
+    }
+
+    NotifyAccessibilityEvent(ax::mojom::Event::kTextChanged, true);
+  }
+
+ private:
+  void UpdateAXLine(const base::string16& line_text,
+                    const size_t line_index,
+                    const gfx::Range& text_range) {
+    auto& ax_lines = GetViewAccessibility().virtual_children();
+
+    // Add a new virtual child for a new line of text.
+    DCHECK(line_index <= ax_lines.size());
+    if (line_index == ax_lines.size()) {
+      auto ax_line = std::make_unique<views::AXVirtualView>();
+      ax_line->GetCustomData().role = ax::mojom::Role::kStaticText;
+      GetViewAccessibility().AddVirtualChildView(std::move(ax_line));
+    }
+
+    // Set the virtual child's name as line text.
+    ui::AXNodeData& ax_node_data = ax_lines[line_index]->GetCustomData();
+    if (base::UTF8ToUTF16(ax_node_data.GetStringAttribute(
+            ax::mojom::StringAttribute::kName)) != line_text) {
+      ax_node_data.SetName(line_text);
+      std::vector<gfx::Rect> bounds = GetSubstringBounds(text_range);
+      DCHECK_EQ(bounds.size(), 1u);
+      ax_node_data.relative_bounds.bounds = gfx::RectF(bounds[0]);
+    }
+  }
+};
+
+BEGIN_METADATA(CaptionBubbleLabel, views::Label)
+END_METADATA
+
 CaptionBubble::CaptionBubble(views::View* anchor,
                              BrowserView* browser_view,
                              base::OnceClosure destroyed_callback)
@@ -345,7 +424,7 @@ void CaptionBubble::Init() {
   // The caption bubble starts out hidden and unable to be activated.
   SetCanActivate(false);
 
-  auto label = std::make_unique<views::Label>();
+  auto label = std::make_unique<CaptionBubbleLabel>();
   label->SetMultiLine(true);
   label->SetMaximumWidth(kMaxWidthDip - kSidePaddingDip * 2);
   label->SetEnabledColor(SK_ColorWHITE);
@@ -366,6 +445,7 @@ void CaptionBubble::Init() {
   title->SetBackgroundColor(SK_ColorTRANSPARENT);
   title->SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_LEFT);
   title->SetText(l10n_util::GetStringUTF16(IDS_LIVE_CAPTION_BUBBLE_TITLE));
+  title->GetViewAccessibility().OverrideIsIgnored(true);
 
   auto error_text = std::make_unique<views::Label>();
   error_text->SetEnabledColor(SK_ColorWHITE);
@@ -510,11 +590,8 @@ void CaptionBubble::OnBlur() {
 }
 
 void CaptionBubble::GetAccessibleNodeData(ui::AXNodeData* node_data) {
+  node_data->role = ax::mojom::Role::kDialog;
   node_data->SetName(title_->GetText());
-  node_data->role = ax::mojom::Role::kCaption;
-  if (model_ && model_->HasError()) {
-    node_data->SetDescription(error_text_->GetText());
-  }
 }
 
 void CaptionBubble::AddedToWidget() {
@@ -564,64 +641,6 @@ void CaptionBubble::OnTextChanged() {
   UpdateBubbleAndTitleVisibility();
   if (GetWidget()->IsVisible())
     inactivity_timer_->Reset();
-
-  // Only update ViewAccessibility if accessibility is enabled.
-  if (content::BrowserAccessibilityState::GetInstance()
-          ->GetAccessibilityMode()
-          .is_mode_off() ||
-      model_->HasError()) {
-    return;
-  }
-
-  auto& virtual_children = GetViewAccessibility().virtual_children();
-  if (text.empty() && !virtual_children.empty()) {
-    GetViewAccessibility().RemoveAllVirtualChildViews();
-    return;
-  }
-
-  const size_t num_lines = GetNumLinesInLabel();
-  size_t start = 0;
-  for (size_t i = 0; i < num_lines - 1; ++i) {
-    size_t end = GetTextIndexOfLineInLabel(i + 1);
-    std::string substring = text.substr(start, end - start);
-    AddVirtualChildView(substring, i, gfx::Range(start, end));
-    start = end;
-  }
-  std::string substring = text.substr(start, text.size() - start);
-  if (!substring.empty()) {
-    AddVirtualChildView(substring, num_lines - 1,
-                        gfx::Range(start, text.size()));
-  }
-
-  // Remove all virtual children that don't have a corresponding line.
-  size_t num_virtual_children = virtual_children.size();
-  for (size_t i = num_lines; i < num_virtual_children; ++i) {
-    GetViewAccessibility().RemoveVirtualChildView(
-        virtual_children.back().get());
-  }
-}
-
-void CaptionBubble::AddVirtualChildView(const std::string& name,
-                                        const size_t line_index,
-                                        const gfx::Range& range) {
-  auto& virtual_children = GetViewAccessibility().virtual_children();
-
-  // Add a new virtual child for a new line of text.
-  DCHECK(line_index <= virtual_children.size());
-  if (line_index == virtual_children.size()) {
-    auto view = std::make_unique<views::AXVirtualView>();
-    GetViewAccessibility().AddVirtualChildView(std::move(view));
-  }
-
-  // Set the virtual child's name as the content of the line.
-  ui::AXNodeData& ax_node_data = virtual_children[line_index]->GetCustomData();
-  if (ax_node_data.GetStringAttribute(ax::mojom::StringAttribute::kName) !=
-      name) {
-    ax_node_data.SetName(name);
-    std::vector<gfx::Rect> bounds = label_->GetSubstringBounds(range);
-    DCHECK_EQ(bounds.size(), 1u);
-    ax_node_data.relative_bounds.bounds = gfx::RectF(bounds[0]);
-  }
 }
 
 void CaptionBubble::OnErrorChanged() {
@@ -632,14 +651,6 @@ void CaptionBubble::OnErrorChanged() {
 
   // The error is only 1 line, so redraw the bubble.
   Redraw();
-
-  if (has_error &&
-      !content::BrowserAccessibilityState::GetInstance()
-           ->GetAccessibilityMode()
-           .is_mode_off() &&
-      !GetViewAccessibility().virtual_children().empty()) {
-    GetViewAccessibility().RemoveAllVirtualChildViews();
-  }
 }
 
 void CaptionBubble::OnIsExpandedChanged() {
@@ -776,18 +787,18 @@ void CaptionBubble::OnInactivityTimeout() {
     GetWidget()->Hide();
 }
 
-std::string CaptionBubble::GetLabelTextForTesting() {
-  return base::UTF16ToUTF8(label_->GetText());
+views::Label* CaptionBubble::GetLabelForTesting() {
+  return static_cast<views::Label*>(label_);
 }
 
-std::vector<std::string> CaptionBubble::GetVirtualChildrenTextForTesting() {
-  auto& virtual_children = GetViewAccessibility().virtual_children();
-  std::vector<std::string> texts;
-  for (auto& virtual_child : virtual_children) {
-    texts.push_back(virtual_child->GetCustomData().GetStringAttribute(
+std::vector<std::string> CaptionBubble::GetAXLineTextForTesting() {
+  auto& ax_lines = label_->GetViewAccessibility().virtual_children();
+  std::vector<std::string> line_texts;
+  for (auto& ax_line : ax_lines) {
+    line_texts.push_back(ax_line->GetCustomData().GetStringAttribute(
         ax::mojom::StringAttribute::kName));
   }
-  return texts;
+  return line_texts;
 }
 
 base::RetainingOneShotTimer* CaptionBubble::GetInactivityTimerForTesting() {

chrome/browser/ui/views/accessibility/caption_bubble.h

@@ -38,6 +38,7 @@ class BrowserView;
 
 namespace captions {
 class CaptionBubbleFrameView;
+class CaptionBubbleLabel;
 
 ///////////////////////////////////////////////////////////////////////////////
 // Caption Bubble
@@ -76,7 +77,7 @@ class CaptionBubble : public views::BubbleDialogDelegateView {
   // Returns the number of lines in the caption bubble label that are rendered.
   size_t GetNumLinesInLabel() const;
 
-  std::string GetLabelTextForTesting();
+  views::Label* GetLabelForTesting();
   base::RetainingOneShotTimer* GetInactivityTimerForTesting();
   void set_tick_clock_for_testing(const base::TickClock* tick_clock) {
     tick_clock_ = tick_clock;
@@ -133,10 +134,7 @@ class CaptionBubble : public views::BubbleDialogDelegateView {
       views::Button::PressedCallback callback,
       const gfx::VectorIcon& icon,
       const int tooltip_text_id);
-  void AddVirtualChildView(const std::string& name,
-                           const size_t i,
-                           const gfx::Range& range);
-  std::vector<std::string> GetVirtualChildrenTextForTesting();
+  std::vector<std::string> GetAXLineTextForTesting();
 
   // After 5 seconds of inactivity, hide the caption bubble. Activity is defined
   // as transcription received from the speech service or user interacting with
@@ -144,7 +142,7 @@ class CaptionBubble : public views::BubbleDialogDelegateView {
   void OnInactivityTimeout();
 
   // Unowned. Owned by views hierarchy.
-  views::Label* label_;
+  CaptionBubbleLabel* label_;
   views::Label* title_;
   views::Label* error_text_;
   views::ImageView* error_icon_;

chrome/browser/ui/views/accessibility/caption_bubble_controller_views.cc

@@ -140,7 +140,10 @@ bool CaptionBubbleControllerViews::IsWidgetVisibleForTesting() {
 }
 
 std::string CaptionBubbleControllerViews::GetBubbleLabelTextForTesting() {
-  return caption_bubble_ ? caption_bubble_->GetLabelTextForTesting() : "";
+  return caption_bubble_
+             ? base::UTF16ToUTF8(
+                   caption_bubble_->GetLabelForTesting()->GetText())  // IN-TEST
+             : "";
 }
 
 }  // namespace captions

chrome/browser/ui/views/accessibility/caption_bubble_controller_views_browsertest.cc

@@ -60,7 +60,8 @@ class CaptionBubbleControllerViewsTest : public InProcessBrowserTest {
   }
 
   views::Label* GetLabel() {
-    return controller_ ? controller_->caption_bubble_->label_ : nullptr;
+    return controller_ ? controller_->caption_bubble_->GetLabelForTesting()
+                       : nullptr;
   }
 
   views::Label* GetTitle() {
@@ -162,8 +163,8 @@ class CaptionBubbleControllerViewsTest : public InProcessBrowserTest {
         browser()->tab_strip_model()->GetWebContentsAt(tab_index));
   }
 
-  std::vector<std::string> GetVirtualChildrenText() {
-    return GetBubble()->GetVirtualChildrenTextForTesting();
+  std::vector<std::string> GetAXLineText() {
+    return GetBubble()->GetAXLineTextForTesting();
   }
 
   void SetTickClockForTesting(const base::TickClock* tick_clock) {
@@ -903,20 +904,20 @@ IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
   // If accessibility is disabled, virtual children aren't computed.
   content::BrowserAccessibilityState::GetInstance()->DisableAccessibility();
   OnFinalTranscription("A dog's nose print");
-  EXPECT_EQ(0u, GetVirtualChildrenText().size());
+  EXPECT_EQ(0u, GetAXLineText().size());
 
   // When accessibility is enabled, virtual children are computed.
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnFinalTranscription("is unique");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("A dog's nose print is unique", GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("A dog's nose print is unique", GetAXLineText()[0]);
 
   // When accessibility is disabled, virtual children are no longer being
   // updated.
   content::BrowserAccessibilityState::GetInstance()->DisableAccessibility();
   OnFinalTranscription("like a fingerprint");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("A dog's nose print is unique", GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("A dog's nose print is unique", GetAXLineText()[0]);
 }
 
 IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
@@ -927,79 +928,55 @@ IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
 
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnPartialTranscription(line);
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ(line, GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ(line, GetAXLineText()[0]);
   OnPartialTranscription(line + line);
-  EXPECT_EQ(2u, GetVirtualChildrenText().size());
-  EXPECT_EQ(line, GetVirtualChildrenText()[0]);
-  EXPECT_EQ(line, GetVirtualChildrenText()[1]);
+  EXPECT_EQ(2u, GetAXLineText().size());
+  EXPECT_EQ(line, GetAXLineText()[0]);
+  EXPECT_EQ(line, GetAXLineText()[1]);
   OnPartialTranscription(line);
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ(line, GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ(line, GetAXLineText()[0]);
 }
 
 IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
                        AccessibleTextClearsWhenBubbleCloses) {
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnFinalTranscription("Dogs' noses are wet to help them smell.");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("Dogs' noses are wet to help them smell.",
-            GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("Dogs' noses are wet to help them smell.", GetAXLineText()[0]);
   ClickButton(GetCloseButton());
-  EXPECT_EQ(0u, GetVirtualChildrenText().size());
+  EXPECT_EQ(0u, GetAXLineText().size());
 }
 
 IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
                        AccessibleTextClearsWhenTabRefreshes) {
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnFinalTranscription("Newfoundlands are amazing lifeguards.");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("Newfoundlands are amazing lifeguards.",
-            GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("Newfoundlands are amazing lifeguards.", GetAXLineText()[0]);
   chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
   content::WaitForLoadStop(
       browser()->tab_strip_model()->GetActiveWebContents());
-  EXPECT_EQ(0u, GetVirtualChildrenText().size());
+  EXPECT_EQ(0u, GetAXLineText().size());
 }
 
 IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
                        AccessibleTextChangesWhenTabChanges) {
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnFinalTranscription("3 dogs survived the Titanic sinking.");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("3 dogs survived the Titanic sinking.",
-            GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("3 dogs survived the Titanic sinking.", GetAXLineText()[0]);
 
   InsertNewTab();
   ActivateTabAt(1);
   OnFinalTranscription("30% of Dalmations are deaf in one ear.", 1);
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("30% of Dalmations are deaf in one ear.",
-            GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("30% of Dalmations are deaf in one ear.", GetAXLineText()[0]);
 
   ActivateTabAt(0);
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("3 dogs survived the Titanic sinking. ",
-            GetVirtualChildrenText()[0]);
-}
-
-IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
-                       AccessibleTextClearsOnError) {
-  content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
-  OnFinalTranscription("The Saluki is the oldest dog breed.");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("The Saluki is the oldest dog breed.", GetVirtualChildrenText()[0]);
-  OnError();
-  EXPECT_EQ(0u, GetVirtualChildrenText().size());
-
-  // Clear the error by refreshing.
-  chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
-  content::WaitForLoadStop(
-      browser()->tab_strip_model()->GetActiveWebContents());
-
-  OnFinalTranscription("Chow Chows have black tongues.");
-  EXPECT_EQ(1u, GetVirtualChildrenText().size());
-  EXPECT_EQ("Chow Chows have black tongues.", GetVirtualChildrenText()[0]);
+  EXPECT_EQ(1u, GetAXLineText().size());
+  EXPECT_EQ("3 dogs survived the Titanic sinking. ", GetAXLineText()[0]);
 }
 
 IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
@@ -1012,28 +989,24 @@ IN_PROC_BROWSER_TEST_F(CaptionBubbleControllerViewsTest,
   }
   content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
   OnFinalTranscription(text);
-  EXPECT_EQ(9u, GetVirtualChildrenText().size());
+  EXPECT_EQ(9u, GetAXLineText().size());
   for (int i = 0; i < 9; i++) {
-    EXPECT_EQ(base::NumberToString(i + 31) + line + " ",
-              GetVirtualChildrenText()[i]);
+    EXPECT_EQ(base::NumberToString(i + 31) + line + " ", GetAXLineText()[i]);
   }
   OnPartialTranscription(text);
-  EXPECT_EQ(39u, GetVirtualChildrenText().size());
+  EXPECT_EQ(39u, GetAXLineText().size());
   for (int i = 0; i < 9; i++) {
-    EXPECT_EQ(base::NumberToString(i + 31) + line + " ",
-              GetVirtualChildrenText()[i]);
+    EXPECT_EQ(base::NumberToString(i + 31) + line + " ", GetAXLineText()[i]);
   }
   for (int i = 10; i < 40; i++) {
-    EXPECT_EQ(base::NumberToString(i) + line + " ",
-              GetVirtualChildrenText()[i - 1]);
+    EXPECT_EQ(base::NumberToString(i) + line + " ", GetAXLineText()[i - 1]);
   }
   OnFinalTranscription("a ");
-  EXPECT_EQ(9u, GetVirtualChildrenText().size());
+  EXPECT_EQ(9u, GetAXLineText().size());
   for (int i = 0; i < 8; i++) {
-    EXPECT_EQ(base::NumberToString(i + 32) + line + " ",
-              GetVirtualChildrenText()[i]);
+    EXPECT_EQ(base::NumberToString(i + 32) + line + " ", GetAXLineText()[i]);
   }
-  EXPECT_EQ("a ", GetVirtualChildrenText()[8]);
+  EXPECT_EQ("a ", GetAXLineText()[8]);
 }
 
 #if !defined(OS_MAC)