Adds auto-close timer.

When hidden, we automatically close ourselves after 5 min.

Bug: b:113129833
Change-Id: I2edb3a73cc31e93234eb7747a91f4314dde56943
Reviewed-on: https://chromium-review.googlesource.com/1188759
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586417}

ash/assistant/assistant_ui_controller.cc

@@ -22,6 +22,9 @@ namespace ash {
 
 namespace {
 
+// When hidden, Assistant will automatically close after |kAutoCloseThreshold|.
+constexpr base::TimeDelta kAutoCloseThreshold = base::TimeDelta::FromMinutes(5);
+
 // Toast -----------------------------------------------------------------------
 
 constexpr int kToastDurationMs = 2500;
@@ -40,7 +43,7 @@ void ShowToast(const std::string& id, int message_id) {
 
 AssistantUiController::AssistantUiController(
     AssistantController* assistant_controller)
-    : assistant_controller_(assistant_controller) {
+    : assistant_controller_(assistant_controller), weak_factory_(this) {
   AddModelObserver(this);
   assistant_controller_->AddObserver(this);
   Shell::Get()->highlighter_controller()->AddObserver(this);
@@ -215,6 +218,18 @@ void AssistantUiController::OnUiVisibilityChanged(
           ? mojom::VoiceInteractionState::RUNNING
           : mojom::VoiceInteractionState::STOPPED);
 
+  if (new_visibility == AssistantVisibility::kHidden) {
+    // When hiding the UI, start a timer to automatically close ourselves after
+    // |kAutoCloseThreshold|. This is to give the user an opportunity to resume
+    // their previous session before it is automatically finished.
+    auto_close_timer_.Start(FROM_HERE, kAutoCloseThreshold,
+                            base::BindRepeating(&AssistantUiController::CloseUi,
+                                                weak_factory_.GetWeakPtr(),
+                                                AssistantSource::kUnspecified));
+  } else {
+    auto_close_timer_.Stop();
+  }
+
   // Metalayer should not be sticky. Disable when the UI is no longer visible.
   if (old_visibility == AssistantVisibility::kVisible)
     Shell::Get()->highlighter_controller()->AbortSession();

ash/assistant/assistant_ui_controller.h

@@ -16,6 +16,7 @@
 #include "ash/assistant/ui/dialog_plate/dialog_plate.h"
 #include "ash/highlighter/highlighter_controller.h"
 #include "base/macros.h"
+#include "base/timer/timer.h"
 #include "ui/views/widget/widget_observer.h"
 
 namespace chromeos {
@@ -120,6 +121,12 @@ class ASH_EXPORT AssistantUiController
   AssistantContainerView* container_view_ =
       nullptr;  // Owned by view hierarchy.
 
+  // When hidden, Assistant automatically closes itself to finish the previous
+  // session. We delay this behavior to allow the user an opportunity to resume.
+  base::OneShotTimer auto_close_timer_;
+
+  base::WeakPtrFactory<AssistantUiController> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AssistantUiController);
 };