assistant: Scroll container when focus changes

Currently UiElementContainerView does not auto scroll when the focus in the
AssistantCardElementView changes, e.g. during Tab traversing.
This patch surfaces the OnFocusChangedInPage event from WebContentsImpl
to NavigableContentsObserver, so that the UiElementContainerView can do
scroll accordinglly.
In this patch, if the bounds of the focused node is clipped by the
container, it will scroll the node to the center of the container.

Bug: 966806
Test: manual
Change-Id: I974db35731b85fdcb957d9898ae921a12dbd7607
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885253
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713180}

ash/app_list/views/search_result_answer_card_view.cc

@@ -298,6 +298,9 @@ class SearchResultAnswerCardView::AnswerCardResultView
     base::RecordAction(base::UserMetricsAction("SearchAnswer_OpenedUrl"));
   }
 
+  void FocusedNodeChanged(bool is_editable_node,
+                          const gfx::Rect& node_bounds_in_screen) override {}
+
   SearchResultContainerView* const container_;  // Not owned.
   AppListViewDelegate* const view_delegate_;    // Not owned.
   mojo::Remote<content::mojom::NavigableContentsFactory> contents_factory_;

ash/assistant/ui/main_stage/assistant_card_element_view.cc

@@ -155,6 +155,19 @@ void AssistantCardElementView::DidSuppressNavigation(
     delegate_->OpenUrlFromView(url);
 }
 
+void AssistantCardElementView::FocusedNodeChanged(
+    bool is_editable_node,
+    const gfx::Rect& node_bounds_in_screen) {
+  // TODO(b/143985066): Card has element with empty bounds, e.g. the line break.
+  if (node_bounds_in_screen.IsEmpty())
+    return;
+
+  gfx::Point origin = node_bounds_in_screen.origin();
+  ConvertPointFromScreen(this, &origin);
+  gfx::Rect focused_rect_in_local(origin, node_bounds_in_screen.size());
+  ScrollRectToVisible(focused_rect_in_local);
+}
+
 void AssistantCardElementView::InitLayout(
     const AssistantCardElement* card_element) {
   SetFocusBehavior(FocusBehavior::ALWAYS);

ash/assistant/ui/main_stage/assistant_card_element_view.h

@@ -39,6 +39,8 @@ class COMPONENT_EXPORT(ASSISTANT_UI) AssistantCardElementView
   void DidSuppressNavigation(const GURL& url,
                              WindowOpenDisposition disposition,
                              bool from_user_gesture) override;
+  void FocusedNodeChanged(bool is_editable_node,
+                          const gfx::Rect& node_bounds_in_screen) override;
 
   // Returns a reference to the native view associated with the underlying web
   // contents. When animating AssistantCardElementView, we should animate the

content/browser/content_service_delegate_impl.cc

@@ -6,6 +6,7 @@
 
 #include "base/macros.h"
 #include "base/optional.h"
+#include "content/public/browser/focused_node_details.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
@@ -197,6 +198,11 @@ class NavigableContentsDelegateImpl : public content::NavigableContentsDelegate,
     client_->UpdateCanGoBack(can_go_back);
   }
 
+  void OnFocusChangedInPage(FocusedNodeDetails* details) override {
+    client_->FocusedNodeChanged(details->is_editable_node,
+                                details->node_bounds_in_screen);
+  }
+
   std::unique_ptr<WebContents> web_contents_;
   mojom::NavigableContentsClient* const client_;
 

services/content/public/cpp/navigable_contents.cc

@@ -106,6 +106,13 @@ void NavigableContents::UpdateContentAXTree(const ui::AXTreeID& id) {
     view_->NotifyAccessibilityTreeChange();
 }
 
+void NavigableContents::FocusedNodeChanged(
+    bool is_editable_node,
+    const gfx::Rect& node_bounds_in_screen) {
+  for (auto& observer : observers_)
+    observer.FocusedNodeChanged(is_editable_node, node_bounds_in_screen);
+}
+
 void NavigableContents::OnEmbedTokenReceived(
     const base::UnguessableToken& token) {
   DCHECK(view_);

services/content/public/cpp/navigable_contents.h

@@ -85,6 +85,8 @@ class COMPONENT_EXPORT(CONTENT_SERVICE_CPP) NavigableContents
                              bool from_user_gesture) override;
   void UpdateCanGoBack(bool can_go_back) override;
   void UpdateContentAXTree(const ui::AXTreeID& id) override;
+  void FocusedNodeChanged(bool is_editable_node,
+                          const gfx::Rect& node_bounds_in_screen) override;
 
   void OnEmbedTokenReceived(const base::UnguessableToken& token);
 

services/content/public/cpp/navigable_contents_observer.h

@@ -9,6 +9,7 @@
 #include "base/observer_list_types.h"
 #include "net/http/http_response_headers.h"
 #include "ui/base/window_open_disposition.h"
+#include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 #include "url/gurl.h"
 
@@ -28,6 +29,8 @@ class COMPONENT_EXPORT(CONTENT_SERVICE_CPP) NavigableContentsObserver
                                      WindowOpenDisposition disposition,
                                      bool from_user_gesture) {}
   virtual void UpdateCanGoBack(bool can_go_back) {}
+  virtual void FocusedNodeChanged(bool is_editable_node,
+                                  const gfx::Rect& node_bounds_in_screen) {}
 };
 
 }  // namespace content

services/content/public/mojom/navigable_contents.mojom

@@ -86,4 +86,8 @@ interface NavigableContentsClient {
   // Informs the client of the ID of the content area's accessibility tree
   // whenever it changes.
   UpdateContentAXTree(ax.mojom.AXTreeID id);
+
+  // Informs the client that the focused DOM node has changed.
+  FocusedNodeChanged(bool is_editable_node,
+                     gfx.mojom.Rect node_bounds_in_screen);
 };

services/content/service_unittest.cc

@@ -45,6 +45,8 @@ class TestNavigableContentsClient : public mojom::NavigableContentsClient {
                              bool from_user_gesture) override {}
   void UpdateCanGoBack(bool can_go_back) override {}
   void UpdateContentAXTree(const ui::AXTreeID& id) override {}
+  void FocusedNodeChanged(bool is_editable_node,
+                          const gfx::Rect& node_bounds_in_screen) override {}
 
   DISALLOW_COPY_AND_ASSIGN(TestNavigableContentsClient);
 };