Do not fire a11y events for caret unless caret or selection is visible

Bug: 870020
Change-Id: Ic0173972f01d506d5e8b18b8c6de629ecc6b6a6e
Reviewed-on: https://chromium-review.googlesource.com/1159188Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583788}

content/browser/accessibility/browser_accessibility.cc

@@ -691,20 +691,24 @@ bool BrowserAccessibility::HasAction(ax::mojom::Action action_enum) const {
   return GetData().HasAction(action_enum);
 }
 
-bool BrowserAccessibility::HasCaret() const {
-  if (IsPlainTextField() &&
-      HasIntAttribute(ax::mojom::IntAttribute::kTextSelStart) &&
-      HasIntAttribute(ax::mojom::IntAttribute::kTextSelEnd)) {
-    return true;
-  }
-
-  // The caret is always at the focus of the selection.
+bool BrowserAccessibility::HasVisibleCaretOrSelection() const {
   int32_t focus_id = manager()->GetTreeData().sel_focus_object_id;
   BrowserAccessibility* focus_object = manager()->GetFromID(focus_id);
   if (!focus_object)
     return false;
 
-  return focus_object->IsDescendantOf(this);
+  // Selection or caret will be visible in a focused editable area.
+  if (HasState(ax::mojom::State::kEditable)) {
+    return IsPlainTextField() ? focus_object == this
+                              : focus_object->IsDescendantOf(this);
+  }
+
+  // The selection will be visible in non-editable content only if it is not
+  // collapsed into a caret.
+  return (focus_id != manager()->GetTreeData().sel_anchor_object_id ||
+          manager()->GetTreeData().sel_focus_offset !=
+              manager()->GetTreeData().sel_anchor_offset) &&
+         focus_object->IsDescendantOf(this);
 }
 
 bool BrowserAccessibility::IsWebAreaForPresentationalIframe() const {

content/browser/accessibility/browser_accessibility.h

@@ -303,8 +303,8 @@ class CONTENT_EXPORT BrowserAccessibility : public ui::AXPlatformNodeDelegate {
   bool HasState(ax::mojom::State state_enum) const;
   bool HasAction(ax::mojom::Action action_enum) const;
 
-  // Returns true if the caret is active on this object.
-  bool HasCaret() const;
+  // Returns true if the caret or selection is visible on this object.
+  bool HasVisibleCaretOrSelection() const;
 
   // True if this is a web area, and its grandparent is a presentational iframe.
   bool IsWebAreaForPresentationalIframe() const;

content/browser/accessibility/browser_accessibility_manager_win.cc

@@ -169,7 +169,7 @@ void BrowserAccessibilityManagerWin::FireGeneratedEvent(
       // Fire the event on the object where the focus of the selection is.
       int32_t focus_id = GetTreeData().sel_focus_object_id;
       BrowserAccessibility* focus_object = GetFromID(focus_id);
-      if (focus_object)
+      if (focus_object->HasVisibleCaretOrSelection())
         FireWinAccessibilityEvent(IA2_EVENT_TEXT_CARET_MOVED, focus_object);
       break;
     }

content/browser/renderer_host/render_widget_host_view_aura.cc

@@ -2389,6 +2389,16 @@ void RenderWidgetHostViewAura::OnSelectionBoundsChanged(
   if (!region)
     return;
 
+  // Do not notify of change unless selection or caret is visible.
+  if (region->anchor == region->focus) {
+    // If selection is collapsed, check to see if user is editing (caret will be
+    // visible).
+    const TextInputState* state = GetTextInputManager()->GetTextInputState();
+    if (!state || (state->type == ui::TEXT_INPUT_TYPE_NONE &&
+                   state->mode == ui::TEXT_INPUT_MODE_NONE))
+      return;
+  }
+
   const gfx::Rect caret_rect = ConvertRectToScreen(gfx::Rect(
       region->focus.edge_top_rounded().x(),
       region->focus.edge_top_rounded().y(), 1, region->focus.GetHeight()));