Sync VoiceOver and system focus on navigation through web content

When navigating in the frame, the "first responder" that has focus is
the view. So when trying to move from frame to web content, the first
responder does not get updated, which makes VO not respond to the focus
events being fired within web content.

This fix is so that when a focus event is fired for the web content,
set it as the first responder if it has not been set yet. This only gets
called by screen readers when navigating with scan mode (arrow keys).

This change has been verified in Mac with VO and in Windows with
NVDA and Narrator (IA2 and UIA).

AccessibilityActionBrowserTest.FocusAction already tests the main action
of BrowserAccessibilityManager::SetFocus.

Bug: 990014
Change-Id: Iaec036a14743c77b26f68ef10b0515aa7034cdf7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1809943Reviewed-by: Ian Prest <iapres@microsoft.com>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702063}

content/browser/accessibility/browser_accessibility_manager.cc

@@ -641,6 +641,8 @@ void BrowserAccessibilityManager::SetFocus(const BrowserAccessibility& node) {
   ui::AXActionData action_data;
   action_data.action = ax::mojom::Action::kFocus;
   action_data.target_node_id = node.GetId();
+  if (!delegate_->AccessibilityViewHasFocus())
+    delegate_->AccessibilityViewSetFocus();
   delegate_->AccessibilityPerformAction(action_data);
 }
 

content/browser/accessibility/browser_accessibility_manager.h

@@ -82,6 +82,7 @@ class CONTENT_EXPORT BrowserAccessibilityDelegate {
 
   virtual void AccessibilityPerformAction(const ui::AXActionData& data) = 0;
   virtual bool AccessibilityViewHasFocus() const = 0;
+  virtual void AccessibilityViewSetFocus() = 0;
   virtual gfx::Rect AccessibilityGetViewBounds() const = 0;
   virtual float AccessibilityGetDeviceScaleFactor() const = 0;
   virtual void AccessibilityFatalError() = 0;

content/browser/accessibility/test_browser_accessibility_delegate.cc

@@ -18,6 +18,8 @@ bool TestBrowserAccessibilityDelegate::AccessibilityViewHasFocus() const {
   return false;
 }
 
+void TestBrowserAccessibilityDelegate::AccessibilityViewSetFocus() {}
+
 gfx::Rect TestBrowserAccessibilityDelegate::AccessibilityGetViewBounds() const {
   return gfx::Rect();
 }

content/browser/accessibility/test_browser_accessibility_delegate.h

@@ -15,6 +15,7 @@ class TestBrowserAccessibilityDelegate : public BrowserAccessibilityDelegate {
 
   void AccessibilityPerformAction(const ui::AXActionData& data) override;
   bool AccessibilityViewHasFocus() const override;
+  void AccessibilityViewSetFocus() override;
   gfx::Rect AccessibilityGetViewBounds() const override;
   float AccessibilityGetDeviceScaleFactor() const override;
   void AccessibilityFatalError() override;

content/browser/frame_host/render_frame_host_impl.cc

@@ -1597,6 +1597,12 @@ bool RenderFrameHostImpl::AccessibilityViewHasFocus() const {
   return false;
 }
 
+void RenderFrameHostImpl::AccessibilityViewSetFocus() {
+  RenderWidgetHostView* view = render_view_host_->GetWidget()->GetView();
+  if (view)
+    view->Focus();
+}
+
 gfx::Rect RenderFrameHostImpl::AccessibilityGetViewBounds() const {
   RenderWidgetHostView* view = render_view_host_->GetWidget()->GetView();
   if (view)

content/browser/frame_host/render_frame_host_impl.h

@@ -328,6 +328,7 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // BrowserAccessibilityDelegate
   void AccessibilityPerformAction(const ui::AXActionData& data) override;
   bool AccessibilityViewHasFocus() const override;
+  void AccessibilityViewSetFocus() override;
   gfx::Rect AccessibilityGetViewBounds() const override;
   float AccessibilityGetDeviceScaleFactor() const override;
   void AccessibilityFatalError() override;