MacViews/a11y: Allow accessibility clients to update the selected text.

ui/views/controls/textfield/textfield.cc

Index: ui/views/controls/textfield/textfield.cc
diff --git a/ui/views/controls/textfield/textfield.cc b/ui/views/controls/textfield/textfield.cc
index c0a889cd339ca675907ca3dedfd1adc1d9b1c6f1..cdc773873cede1250cf6c3e3c213614f09d86fe5 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -486,6 +486,7 @@ const gfx::Range& Textfield::GetSelectedRange() const {
 void Textfield::SelectRange(const gfx::Range& range) {
   model_->SelectRange(range);
   UpdateAfterChange(false, true);
+  NotifyAccessibilityEvent(ui::AX_EVENT_TEXT_SELECTION_CHANGED, true);
 }
 
 const gfx::SelectionModel& Textfield::GetSelectionModel() const {
@@ -937,6 +938,9 @@ void Textfield::GetAccessibleState(ui::AXViewState* state) {
     state->set_value_callback =
         base::Bind(&Textfield::AccessibilitySetValue,
                    weak_ptr_factory_.GetWeakPtr());
+    state->replace_selection_callback =
+        base::Bind(&Textfield::AccessibilityReplaceSelection,
+                   weak_ptr_factory_.GetWeakPtr());
   }
 }
 
@@ -1777,6 +1781,13 @@ void Textfield::AccessibilitySetValue(const base::string16& new_value) {
   }
 }
 
+void Textfield::AccessibilityReplaceSelection(const base::string16& new_value) {
+  if (!read_only()) {
+    InsertOrReplaceText(new_value);
+    ClearSelection();

[tapted, 2016/09/27 07:16:30]

do we want to extend the selection here too?

[Patti Lor, 2016/10/20 04:19:34]

No - Cocoa doesn't, so I was following that behaviour.

+  }
+}
+
 void Textfield::UpdateBackgroundColor() {
   const SkColor color = GetBackgroundColor();
   if (ui::MaterialDesignController::IsSecondaryUiMaterial()) {