assistant: Remove DCHECK of Assistant structure

This cl fixes two issues:
1. When app_list is not active, we should not request focus to
assistant_page_view. Otherwise, the active window info will lose so that
we cannot get the assistant structure of the active window.

2. The DCHECK of |assistant_tree_| or |assistant_extra_| is not valid
because they could be nullptr if there is not such an active window.

Bug: b/139363094
Test: manual
Change-Id: I3b78688b15047925dc92f613fe9e46b198d864fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017982
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738284}

ash/app_list/app_list_util.cc

@@ -118,11 +118,6 @@ void UpdateActivationForAppListView(AppListView* app_list_view,
     return;
 
   widget->Show();
-
-  // Refocus the embedded assistant page after widget activation.
-  auto* contents_view = app_list_view->app_list_main_view()->contents_view();
-  if (contents_view->IsShowingEmbeddedAssistantUI())
-    contents_view->FocusEmbeddedAssistantPage();
 }
 
 }  // namespace ash

ash/app_list/views/app_list_view.cc

@@ -1328,7 +1328,15 @@ AppListStateTransitionSource AppListView::GetAppListStateTransitionSource(
 }
 
 views::View* AppListView::GetInitiallyFocusedView() {
-  return app_list_main_view_->search_box_view()->search_box();
+  views::View* initial_view;
+  if (IsShowingEmbeddedAssistantUI()) {
+    // Assistant page will redirect focus to its subviews.
+    auto* content = app_list_main_view_->contents_view();
+    initial_view = content->GetPageView(content->GetActivePageIndex());
+  } else {
+    initial_view = app_list_main_view_->search_box_view()->search_box();
+  }
+  return initial_view;
 }
 
 void AppListView::OnScrollEvent(ui::ScrollEvent* event) {
@@ -1577,7 +1585,7 @@ void AppListView::SetState(AppListViewState new_state) {
   if (is_in_drag_ && app_list_state_ != AppListViewState::kClosed)
     app_list_main_view_->contents_view()->UpdateYPositionAndOpacity();
 
-  if (GetWidget()->IsActive() && !IsShowingEmbeddedAssistantUI()) {
+  if (GetWidget()->IsActive()) {
     // Reset the focus to initially focused view. This should be
     // done before updating visibility of views, because setting
     // focused view invisible automatically moves focus to next

ash/app_list/views/assistant/assistant_page_view.cc

@@ -234,6 +234,10 @@ void AssistantPageView::OnUiVisibilityChanged(
     return;
   }
 
+  // Assistant page will get focus when widget shown.
+  if (GetWidget() && GetWidget()->IsActive())
+    RequestFocus();
+
   const bool prefer_voice =
       assistant_view_delegate_->IsTabletMode() ||
       AssistantState::Get()->launch_with_mic_open().value_or(false);

ash/app_list/views/contents_view.cc

@@ -357,14 +357,6 @@ void ContentsView::ShowEmbeddedAssistantUI(bool show) {
   // Hide or Show results.
   auto* page_view = GetPageView(assistant_page);
   page_view->SetVisible(show);
-  if (show) {
-    page_view->RequestFocus();
-    // RequestFocus() might cause ResetForShow() method through
-    // AppListView::OnHomeLauncherGainingFocusWithoutAnimation() and it can hide
-    // |page_view|. Thus |page_view|'s visibility should be set again. See
-    // b/140831868.
-    page_view->SetVisible(show);
-  }
 
   const int search_results_page =
       GetPageIndexForState(AppListState::kStateSearchResults);

chromeos/services/assistant/assistant_manager_service_impl.cc

@@ -455,9 +455,9 @@ void AssistantManagerServiceImpl::StartCachedScreenContextInteraction() {
     return;
 
   // It is illegal to call this method without having first cached screen
-  // context (see CacheScreenContext()).
-  DCHECK(assistant_extra_);
-  DCHECK(assistant_tree_);
+  // context (see CacheScreenContext()). |assistant_extra_| and
+  // |assistant_tree_| could be nullptr if there is no active browser or ARC.
+  // window.
   DCHECK(!assistant_screenshot_.empty());
 
   SendScreenContextRequest(assistant_extra_.get(), assistant_tree_.get(),