Finish conversation starters.

This involved:
- Limiting conversation starter count to 3.
- Shuffling and selecting conversation starters to reach 3.
- Refreshing conversation starter cache for new UI sessions.
- Center aligning conversation starters (but keeping suggestion chips
  for interaction responses start aligned).

Bug: b:111694337
Change-Id: I1b5b94fabcd0a37ce3a3400a670db4224fc6a667
Reviewed-on: https://chromium-review.googlesource.com/1182863
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584916}

ash/assistant/assistant_cache_controller.cc

@@ -6,26 +6,42 @@
 
 #include <vector>
 
+#include "ash/assistant/assistant_controller.h"
+#include "ash/assistant/assistant_ui_controller.h"
 #include "ash/assistant/util/deep_link_util.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/voice_interaction/voice_interaction_controller.h"
+#include "base/rand_util.h"
 #include "chromeos/services/assistant/public/mojom/assistant.mojom.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace ash {
 
-AssistantCacheController::AssistantCacheController()
-    : voice_interaction_binding_(this) {
+namespace {
+
+// Conversation starters.
+constexpr int kNumOfConversationStarters = 3;
+
+}  // namespace
+
+AssistantCacheController::AssistantCacheController(
+    AssistantController* assistant_controller)
+    : assistant_controller_(assistant_controller),
+      voice_interaction_binding_(this) {
   UpdateConversationStarters();
 
+  assistant_controller_->AddObserver(this);
+
   // Bind to observe changes to screen context preference.
   mojom::VoiceInteractionObserverPtr ptr;
   voice_interaction_binding_.Bind(mojo::MakeRequest(&ptr));
   Shell::Get()->voice_interaction_controller()->AddObserver(std::move(ptr));
 }
 
-AssistantCacheController::~AssistantCacheController() = default;
+AssistantCacheController::~AssistantCacheController() {
+  assistant_controller_->RemoveObserver(this);
+}
 
 void AssistantCacheController::AddModelObserver(
     AssistantCacheModelObserver* observer) {
@@ -37,6 +53,22 @@ void AssistantCacheController::RemoveModelObserver(
   model_.RemoveObserver(observer);
 }
 
+void AssistantCacheController::OnAssistantControllerConstructed() {
+  assistant_controller_->ui_controller()->AddModelObserver(this);
+}
+
+void AssistantCacheController::OnAssistantControllerDestroying() {
+  assistant_controller_->ui_controller()->RemoveModelObserver(this);
+}
+
+void AssistantCacheController::OnUiVisibilityChanged(bool visible,
+                                                     AssistantSource source) {
+  // When hiding the UI we update our cache of conversation starters so that
+  // they're fresh for the next session.
+  if (!visible)
+    UpdateConversationStarters();
+}
+
 void AssistantCacheController::OnVoiceInteractionContextEnabled(bool enabled) {
   UpdateConversationStarters();
 }
@@ -56,22 +88,34 @@ void AssistantCacheController::UpdateConversationStarters() {
     conversation_starters.push_back(std::move(starter));
   };
 
+  // Always show the "What can you do?" conversation starter.
   AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_WHAT_CAN_YOU_DO);
 
+  // Always show the "What's on my screen?" conversation starter (if enabled).
   if (Shell::Get()->voice_interaction_controller()->context_enabled()) {
     AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_WHATS_ON_MY_SCREEN,
                            assistant::util::CreateWhatsOnMyScreenDeepLink());
   }
 
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_WHATS_ON_MY_CALENDAR);
+  // The rest of the conversation starters will be shuffled...
+  int shuffled_message_ids[] = {
+      IDS_ASH_ASSISTANT_CHIP_IM_BORED,
+      IDS_ASH_ASSISTANT_CHIP_OPEN_FILES,
+      IDS_ASH_ASSISTANT_CHIP_PLAY_MUSIC,
+      IDS_ASH_ASSISTANT_CHIP_SEND_AN_EMAIL,
+      IDS_ASH_ASSISTANT_CHIP_SET_A_REMINDER,
+      IDS_ASH_ASSISTANT_CHIP_WHATS_ON_MY_CALENDAR,
+      IDS_ASH_ASSISTANT_CHIP_WHATS_THE_WEATHER,
+  };
+
+  base::RandomShuffle(std::begin(shuffled_message_ids),
+                      std::end(shuffled_message_ids));
 
-  // TODO(dmblack): Shuffle these chips and limit our total chip count to four.
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_PLAY_MUSIC);
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_SEND_AN_EMAIL);
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_WHATS_THE_WEATHER);
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_IM_BORED);
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_OPEN_FILES);
-  AddConversationStarter(IDS_ASH_ASSISTANT_CHIP_SET_A_REMINDER);
+  // ...and will be added until we reach |kNumOfConversationStarters|.
+  for (int i = 0; conversation_starters.size() < kNumOfConversationStarters;
+       ++i) {
+    AddConversationStarter(shuffled_message_ids[i]);
+  }
 
   model_.SetConversationStarters(std::move(conversation_starters));
 }

ash/assistant/assistant_cache_controller.h

@@ -5,7 +5,9 @@
 #ifndef ASH_ASSISTANT_ASSISTANT_CACHE_CONTROLLER_H_
 #define ASH_ASSISTANT_ASSISTANT_CACHE_CONTROLLER_H_
 
+#include "ash/assistant/assistant_controller_observer.h"
 #include "ash/assistant/model/assistant_cache_model.h"
+#include "ash/assistant/model/assistant_ui_model_observer.h"
 #include "ash/public/interfaces/voice_interaction_controller.mojom.h"
 #include "base/macros.h"
 #include "mojo/public/cpp/bindings/binding.h"
@@ -13,10 +15,13 @@
 namespace ash {
 
 class AssistantCacheModelObserver;
+class AssistantController;
 
-class AssistantCacheController : public mojom::VoiceInteractionObserver {
+class AssistantCacheController : public AssistantControllerObserver,
+                                 public AssistantUiModelObserver,
+                                 public mojom::VoiceInteractionObserver {
  public:
-  AssistantCacheController();
+  explicit AssistantCacheController(AssistantController* assistant_controller);
   ~AssistantCacheController() override;
 
   // Returns a reference to the underlying model.
@@ -26,6 +31,13 @@ class AssistantCacheController : public mojom::VoiceInteractionObserver {
   void AddModelObserver(AssistantCacheModelObserver* observer);
   void RemoveModelObserver(AssistantCacheModelObserver* observer);
 
+  // AssistantControllerObserver:
+  void OnAssistantControllerConstructed() override;
+  void OnAssistantControllerDestroying() override;
+
+  // AssistantUiModelObserver:
+  void OnUiVisibilityChanged(bool visible, AssistantSource source) override;
+
  private:
   // mojom::VoiceInteractionObserver:
   void OnVoiceInteractionStatusChanged(
@@ -39,6 +51,8 @@ class AssistantCacheController : public mojom::VoiceInteractionObserver {
 
   void UpdateConversationStarters();
 
+  AssistantController* const assistant_controller_;  // Owned by Shell.
+
   mojo::Binding<mojom::VoiceInteractionObserver> voice_interaction_binding_;
 
   AssistantCacheModel model_;

ash/assistant/assistant_controller.cc

@@ -25,7 +25,8 @@ namespace ash {
 
 AssistantController::AssistantController()
     : assistant_volume_control_binding_(this),
-      assistant_cache_controller_(std::make_unique<AssistantCacheController>()),
+      assistant_cache_controller_(
+          std::make_unique<AssistantCacheController>(this)),
       assistant_interaction_controller_(
           std::make_unique<AssistantInteractionController>(this)),
       assistant_notification_controller_(

ash/assistant/ui/main_stage/suggestion_container_view.cc

@@ -55,18 +55,25 @@ int SuggestionContainerView::GetHeightForWidth(int width) const {
 
 void SuggestionContainerView::OnContentsPreferredSizeChanged(
     views::View* content_view) {
-  const int preferred_width = content_view->GetPreferredSize().width();
-  content_view->SetSize(gfx::Size(preferred_width, kPreferredHeightDip));
+  // Our contents should never be smaller than our container width because when
+  // showing conversation starters we will be center aligned.
+  const int width =
+      std::max(content_view->GetPreferredSize().width(), this->width());
+  content_view->SetSize(gfx::Size(width, kPreferredHeightDip));
 }
 
 void SuggestionContainerView::InitLayout() {
-  views::BoxLayout* layout_manager =
+  layout_manager_ =
       content_view()->SetLayoutManager(std::make_unique<views::BoxLayout>(
           views::BoxLayout::Orientation::kHorizontal,
           gfx::Insets(0, kPaddingDip), kSpacingDip));
 
-  layout_manager->set_cross_axis_alignment(
+  layout_manager_->set_cross_axis_alignment(
       views::BoxLayout::CrossAxisAlignment::CROSS_AXIS_ALIGNMENT_END);
+
+  // We center align when showing conversation starters.
+  layout_manager_->set_main_axis_alignment(
+      views::BoxLayout::MainAxisAlignment::MAIN_AXIS_ALIGNMENT_CENTER);
 }
 
 void SuggestionContainerView::OnConversationStartersChanged(
@@ -81,6 +88,11 @@ void SuggestionContainerView::OnResponseChanged(
   has_received_response_ = true;
 
   OnSuggestionsCleared();
+
+  // When no longer showing conversation starters, we start align our content.
+  layout_manager_->set_main_axis_alignment(
+      views::BoxLayout::MainAxisAlignment::MAIN_AXIS_ALIGNMENT_START);
+
   OnSuggestionsChanged(response.GetSuggestions());
 }
 
@@ -183,6 +195,11 @@ void SuggestionContainerView::OnUiVisibilityChanged(bool visible,
   } else {
     // Reset view state.
     has_received_response_ = false;
+
+    // When we become visible again we will be showing conversation starters so
+    // we need to center align our content.
+    layout_manager_->set_main_axis_alignment(
+        views::BoxLayout::MainAxisAlignment::MAIN_AXIS_ALIGNMENT_CENTER);
   }
 }
 

ash/assistant/ui/main_stage/suggestion_container_view.h

@@ -16,6 +16,10 @@
 #include "chromeos/services/assistant/public/mojom/assistant.mojom.h"
 #include "ui/views/controls/scroll_view.h"
 
+namespace views {
+class BoxLayout;
+}  // namespace views
+
 namespace ash {
 
 class AssistantController;
@@ -68,6 +72,8 @@ class SuggestionContainerView : public AssistantScrollView,
 
   AssistantController* const assistant_controller_;  // Owned by Shell.
 
+  views::BoxLayout* layout_manager_;  // Owned by view hierarchy.
+
   // Cache of suggestion chip views owned by the view hierarchy. The key for the
   // map is the unique identifier by which the Assistant interaction model
   // identifies the view's underlying suggestion.