Chromecast should focus on full screen shell surface ax node

Chromecast should focus on the full screen shell surface node
that holds the child tree for the UI.  Otherwise, things like
live regions will fail to find a focused root node and will
not work.

Bug: NONE
Test: Local chromecast build
Change-Id: I5b34eb40fd3c7240b8584fc83bf312727f9e2658
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2134568Reviewed-by: Sean Topping <seantopping@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758839}

chromecast/browser/DEPS

@@ -16,6 +16,7 @@ include_rules = [
   "+components/cdm/browser",
   "+components/crash",
   "+components/download/public/common",
+  "+components/exo",
   "+components/heap_profiling",
   "+components/keyed_service",
   "+components/network_hints",

chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.cc

@@ -7,6 +7,9 @@
 #include "chromecast/browser/accessibility/accessibility_manager.h"
 #include "chromecast/browser/cast_browser_process.h"
 #include "chromecast/browser/ui/aura/accessibility/automation_manager_aura.h"
+#include "components/exo/fullscreen_shell_surface.h"
+#include "components/exo/shell_surface_util.h"
+#include "components/exo/surface.h"
 #include "ui/accessibility/ax_action_data.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/ax_tree_data.h"
@@ -14,17 +17,20 @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
+#include "ui/views/accessibility/ax_view_obj_wrapper.h"
 
 AXTreeSourceAura::AXTreeSourceAura(views::AXAuraObjWrapper* root,
                                    const ui::AXTreeID& tree_id,
                                    views::AXAuraObjCache* cache)
-    : AXTreeSourceViews(root, tree_id, cache) {}
+    : AXTreeSourceViews(root, tree_id, cache), cache_(cache) {}
 
 AXTreeSourceAura::~AXTreeSourceAura() = default;
 
 bool AXTreeSourceAura::GetTreeData(ui::AXTreeData* tree_data) const {
   AXTreeSourceViews::GetTreeData(tree_data);
 
+  // TODO(b/1069055) : This is a temporary solution to override the
+  // superclass method which does not set the correct focus_id.
   aura::Window* root_window =
       chromecast::shell::CastBrowserProcess::GetInstance()
           ->accessibility_manager()
@@ -35,8 +41,37 @@ bool AXTreeSourceAura::GetTreeData(ui::AXTreeData* tree_data) const {
         aura::client::GetFocusClient(root_window);
     if (focus_client) {
       aura::Window* window = focus_client->GetFocusedWindow();
-      tree_data->focus_id =
-          AutomationManagerAura::GetInstance()->GetIDFromWindow(window);
+      tree_data->focus_id = ui::AXNode::kInvalidAXID;
+
+      // Search for the full screen shell surface that holds the child
+      // tree for our UI. This is the node that should receive focus.
+      if (window) {
+        std::stack<aura::Window*> stack;
+        stack.push(window);
+        while (!stack.empty()) {
+          aura::Window* top = stack.top();
+          stack.pop();
+          DCHECK(top);
+
+          exo::Surface* surface = exo::GetShellMainSurface(top);
+          if (surface) {
+            views::Widget* widget =
+                views::Widget::GetWidgetForNativeWindow(top);
+            if (widget) {
+              exo::FullscreenShellSurface* full_screen_shell_surface =
+                  static_cast<exo::FullscreenShellSurface*>(
+                      widget->widget_delegate());
+              tree_data->focus_id = cache_->GetID(full_screen_shell_surface);
+              break;
+            }
+          }
+          for (aura::Window* child : top->children())
+            stack.push(child);
+        }
+        if (tree_data->focus_id == -1) {
+          LOG(ERROR) << "Could not find node to focus in desktop tree.";
+        }
+      }
     }
   }
   return true;

chromecast/browser/ui/aura/accessibility/ax_tree_source_aura.h

@@ -25,6 +25,8 @@ class AXTreeSourceAura : public views::AXTreeSourceViews {
                      ui::AXNodeData* out_data) const override;
 
  private:
+  views::AXAuraObjCache* cache_;
+
   DISALLOW_COPY_AND_ASSIGN(AXTreeSourceAura);
 };