app_list: Make the Assistant card scrollable

This patch addes a window property to make the Assistant answer card
scrollable in the embedded UI.
Changes:
1. Refactor current code so that app_list_view can access the window
   property.
2. Modify app_list_view event targeter to handle Assistant answer card
   events.

Bug: 924624
Test: manual
Change-Id: Iad9650ca98589793ff065574b3971aa97c3ec3f5
Reviewed-on: https://chromium-review.googlesource.com/c/1482591Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634774}

ash/app_list/views/app_list_view.cc

@@ -15,6 +15,7 @@
 #include "ash/app_list/views/apps_container_view.h"
 #include "ash/app_list/views/contents_view.h"
 #include "ash/app_list/views/search_box_view.h"
+#include "ash/assistant/ui/assistant_ui_constants.h"
 #include "ash/public/cpp/app_list/app_list_config.h"
 #include "ash/public/cpp/app_list/app_list_features.h"
 #include "ash/public/cpp/shell_window_ids.h"
@@ -157,6 +158,14 @@ class AppListEventTargeter : public aura::WindowTargeter {
       if (event.type() != ui::ET_MOUSE_MOVED)
         return false;
     }
+
+    if (window->GetProperty(ash::assistant::ui::kOnlyAllowMouseClickEvents)) {
+      if (event.type() != ui::ET_MOUSE_PRESSED &&
+          event.type() != ui::ET_MOUSE_RELEASED) {
+        return false;
+      }
+    }
+
     return aura::WindowTargeter::SubtreeShouldBeExploredForEvent(window, event);
   }
 

ash/assistant/ui/BUILD.gn

@@ -7,7 +7,11 @@ import("//chromeos/assistant/assistant.gni")
 
 assert(is_chromeos)
 
-source_set("constants") {
+component("constants") {
+  output_name = "assistant_ui_constants"
+
+  defines = [ "IS_ASSISTANT_UI_CONSTANTS_IMPL" ]
+
   sources = [
     "assistant_ui_constants.cc",
     "assistant_ui_constants.h",
@@ -16,6 +20,8 @@ source_set("constants") {
   deps = [
     "//base",
     "//skia",
+    "//ui/aura",
+    "//ui/base",
     "//ui/gfx",
   ]
 }

ash/assistant/ui/assistant_container_view.cc

@@ -37,9 +37,6 @@ namespace {
 // Appearance.
 constexpr SkColor kBackgroundColor = SK_ColorWHITE;
 
-// Window properties.
-DEFINE_UI_CLASS_PROPERTY_KEY(bool, kOnlyAllowMouseClickEvents, false)
-
 // AssistantContainerClientView ------------------------------------------------
 
 // AssistantContainerClientView is the client view for AssistantContainerView
@@ -130,7 +127,7 @@ class AssistantContainerEventTargeter : public aura::WindowTargeter {
   // aura::WindowTargeter:
   bool SubtreeShouldBeExploredForEvent(aura::Window* window,
                                        const ui::LocatedEvent& event) override {
-    if (window->GetProperty(kOnlyAllowMouseClickEvents)) {
+    if (window->GetProperty(assistant::ui::kOnlyAllowMouseClickEvents)) {
       if (event.type() != ui::ET_MOUSE_PRESSED &&
           event.type() != ui::ET_MOUSE_RELEASED) {
         return false;
@@ -273,11 +270,6 @@ AssistantContainerView::~AssistantContainerView() {
   delegate_->RemoveUiModelObserver(this);
 }
 
-// static
-void AssistantContainerView::OnlyAllowMouseClickEvents(aura::Window* window) {
-  window->SetProperty(kOnlyAllowMouseClickEvents, true);
-}
-
 const char* AssistantContainerView::GetClassName() const {
   return "AssistantContainerView";
 }

ash/assistant/ui/assistant_container_view.h

@@ -13,10 +13,6 @@
 #include "base/macros.h"
 #include "ui/views/bubble/bubble_dialog_delegate_view.h"
 
-namespace aura {
-class Window;
-}  // namespace aura
-
 namespace ash {
 
 class AssistantContainerViewAnimator;
@@ -32,11 +28,6 @@ class COMPONENT_EXPORT(ASSISTANT_UI) AssistantContainerView
   explicit AssistantContainerView(AssistantViewDelegate* delegate);
   ~AssistantContainerView() override;
 
-  // Instructs the event targeter for the Assistant window to only allow mouse
-  // click events to reach the specified |window|. All other events will not
-  // be explored by |window|'s subtree for handling.
-  static void OnlyAllowMouseClickEvents(aura::Window* window);
-
   // views::BubbleDialogDelegateView:
   const char* GetClassName() const override;
   void AddedToWidget() override;

ash/assistant/ui/assistant_ui_constants.cc

@@ -5,12 +5,15 @@
 #include "ash/assistant/ui/assistant_ui_constants.h"
 
 #include "base/no_destructor.h"
+#include "ui/base/class_property.h"
 #include "ui/gfx/font_list.h"
 
 namespace ash {
 namespace assistant {
 namespace ui {
 
+DEFINE_UI_CLASS_PROPERTY_KEY(bool, kOnlyAllowMouseClickEvents, false)
+
 const gfx::FontList& GetDefaultFontList() {
   static const base::NoDestructor<gfx::FontList> font_list("Google Sans, 12px");
   return *font_list;

ash/assistant/ui/assistant_ui_constants.h

@@ -5,7 +5,9 @@
 #ifndef ASH_ASSISTANT_UI_ASSISTANT_UI_CONSTANTS_H_
 #define ASH_ASSISTANT_UI_ASSISTANT_UI_CONSTANTS_H_
 
+#include "base/component_export.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/aura/window.h"
 #include "ui/gfx/color_palette.h"
 
 namespace gfx {
@@ -32,7 +34,14 @@ constexpr SkColor kTextColorSecondary = gfx::kGoogleGrey700;
 namespace assistant {
 namespace ui {
 
+// Window property to instruct the event targeter for the Assistant window to
+// only allow mouse click events to reach the specified |window|. All other
+// events will not be explored by |window|'s subtree for handling.
+COMPONENT_EXPORT(ASSISTANT_UI_CONSTANTS)
+extern const aura::WindowProperty<bool>* const kOnlyAllowMouseClickEvents;
+
 // Returns the default font list for Assistant UI.
+COMPONENT_EXPORT(ASSISTANT_UI_CONSTANTS)
 const gfx::FontList& GetDefaultFontList();
 
 }  // namespace ui

ash/assistant/ui/main_stage/assistant_card_element_view.cc

@@ -8,7 +8,9 @@
 
 #include "ash/assistant/model/assistant_ui_element.h"
 #include "ash/assistant/ui/assistant_container_view.h"
+#include "ash/assistant/ui/assistant_ui_constants.h"
 #include "ash/assistant/ui/assistant_view_delegate.h"
+#include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/events/event.h"
 #include "ui/events/event_sink.h"
@@ -80,7 +82,7 @@ void AssistantCardElementView::AddedToWidget() {
   // vertically. As such, we need to prevent the Assistant card window from
   // receiving events it doesn't need. It needs mouse click events for
   // handling links.
-  AssistantContainerView::OnlyAllowMouseClickEvents(window);
+  window->SetProperty(ash::assistant::ui::kOnlyAllowMouseClickEvents, true);
 }
 
 void AssistantCardElementView::ChildPreferredSizeChanged(views::View* child) {