cros: Fix unnecessary black shelf background issue when device boot

This CL is more lightweight solution compared with the previous
attempts:
https://crrev.com/c/1229695
(An overkill. "no wallpaper" is not a valid UI state we'll support.)
https://crrev.com/c/1187547
(A risky change. Large number of tests failed.)
https://crrev.com/c/1173433
(Doesn't quite handle the "no wallpaper" case.)

Bug: 874015
Change-Id: I7656856d1b631b7f6d2555f932116ea08e7d23ec
Reviewed-on: https://chromium-review.googlesource.com/1237149Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594504}

ash/shelf/shelf_background_animator_unittest.cc

@@ -358,28 +358,19 @@ class ShelfBackgroundTargetColorTest : public NoSessionAshTestBase {
   DISALLOW_COPY_AND_ASSIGN(ShelfBackgroundTargetColorTest);
 };
 
-// Verify the target colors of the shelf and item backgrounds are updated after
-// session state changes. Only compare the base color, because different alpha
-// values may be applied based on |ShelfBackgroundType|, which is verifed by
+// The tests only compare the base color, because different alpha values may be
+// applied based on |ShelfBackgroundType|, which is verifed by
 // |ShelfBackgroundAnimatorTest|.
+//
+// Verify the target colors of the shelf and item backgrounds are updated based
+// on session state, starting from LOGIN_PRIMARY.
 TEST_F(ShelfBackgroundTargetColorTest,
-       ShelfAndItemBackgroundColorUpdatedWithSessionState) {
-  // Use the real ShelfBackgroundAnimator instance because it needs to update
-  // for session state changes.
+       ShelfAndItemBackgroundColorUpdatedFromLogin) {
   ShelfBackgroundAnimatorTestApi test_api(
       Shelf::ForWindow(Shell::Get()->GetPrimaryRootWindow())
           ->shelf_widget()
           ->background_animator_for_testing());
 
-  // The shelf is not initialized until session state becomes active, so the
-  // following two cases don't have visible effects until we support views-based
-  // shelf for all session states, but it's still good to check them here.
-  NotifySessionStateChanged(session_manager::SessionState::OOBE);
-  EXPECT_EQ(GetBaseColor(test_api.shelf_background_target_color()),
-            GetBaseColor(SK_ColorTRANSPARENT));
-  EXPECT_EQ(GetBaseColor(test_api.item_background_target_color()),
-            GetBaseColor(gfx::kGoogleGrey100));
-
   NotifySessionStateChanged(session_manager::SessionState::LOGIN_PRIMARY);
   EXPECT_EQ(GetBaseColor(test_api.shelf_background_target_color()),
             GetBaseColor(SK_ColorTRANSPARENT));
@@ -431,4 +422,39 @@ TEST_F(ShelfBackgroundTargetColorTest,
             GetBaseColor(kShelfDefaultBaseColor));
 }
 
+// Verify the target colors of the shelf and item backgrounds are updated based
+// on session state, starting from OOBE.
+// Note: the shelf is not supported for OOBE yet but it's good to check it here.
+// TODO(wzang|798869): The item backgrounds still keep the OOBE color if
+// directly transitioned from OOBE to LOGIN_PRIMARY. Revisit this when OOBE
+// shelf is supported.
+TEST_F(ShelfBackgroundTargetColorTest,
+       ShelfAndItemBackgroundColorUpdatedFromOOBE) {
+  ShelfBackgroundAnimatorTestApi test_api(
+      Shelf::ForWindow(Shell::Get()->GetPrimaryRootWindow())
+          ->shelf_widget()
+          ->background_animator_for_testing());
+
+  NotifySessionStateChanged(session_manager::SessionState::OOBE);
+  EXPECT_EQ(GetBaseColor(test_api.shelf_background_target_color()),
+            GetBaseColor(SK_ColorTRANSPARENT));
+  EXPECT_EQ(GetBaseColor(test_api.item_background_target_color()),
+            GetBaseColor(gfx::kGoogleGrey100));
+
+  SimulateUserLogin("user1@test.com");
+
+  NotifySessionStateChanged(
+      session_manager::SessionState::LOGGED_IN_NOT_ACTIVE);
+  EXPECT_EQ(GetBaseColor(test_api.shelf_background_target_color()),
+            GetBaseColor(SK_ColorTRANSPARENT));
+  EXPECT_EQ(GetBaseColor(test_api.item_background_target_color()),
+            GetBaseColor(SK_ColorTRANSPARENT));
+
+  NotifySessionStateChanged(session_manager::SessionState::ACTIVE);
+  EXPECT_EQ(GetBaseColor(test_api.shelf_background_target_color()),
+            GetBaseColor(kShelfDefaultBaseColor));
+  EXPECT_EQ(GetBaseColor(test_api.item_background_target_color()),
+            GetBaseColor(kShelfDefaultBaseColor));
+}
+
 }  // namespace ash

ash/shelf/shelf_layout_manager.cc

@@ -541,8 +541,10 @@ ShelfBackgroundType ShelfLayoutManager::GetShelfBackgroundType() const {
   if (state_.session_state == session_manager::SessionState::OOBE)
     return SHELF_BACKGROUND_OOBE;
   if (state_.session_state != session_manager::SessionState::ACTIVE) {
-    if (!Shell::Get()->wallpaper_controller()->IsWallpaperBlurred())
+    if (Shell::Get()->wallpaper_controller()->HasShownAnyWallpaper() &&
+        !Shell::Get()->wallpaper_controller()->IsWallpaperBlurred()) {
       return SHELF_BACKGROUND_LOGIN_NONBLURRED_WALLPAPER;
+    }
     return SHELF_BACKGROUND_LOGIN;
   }
 
@@ -1143,6 +1145,10 @@ void ShelfLayoutManager::OnWallpaperBlurChanged() {
   MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
 }
 
+void ShelfLayoutManager::OnFirstWallpaperShown() {
+  MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
+}
+
 void ShelfLayoutManager::OnLoginStatusChanged(LoginStatus loing_status) {
   UpdateVisibilityState();
 }

ash/shelf/shelf_layout_manager.h

@@ -187,6 +187,7 @@ class ASH_EXPORT ShelfLayoutManager
 
   // Overridden from WallpaperControllerObserver:
   void OnWallpaperBlurChanged() override;
+  void OnFirstWallpaperShown() override;
 
   // TODO(harrym|oshima): These templates will be moved to a new Shelf class.
   // A helper function for choosing values specific to a shelf alignment.

ash/shelf/shelf_layout_manager_unittest.cc

@@ -253,6 +253,29 @@ class ShelfLayoutObserverTest : public ShelfLayoutManagerObserver {
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutObserverTest);
 };
 
+class WallpaperShownWaiter : public WallpaperControllerObserver {
+ public:
+  WallpaperShownWaiter() {
+    Shell::Get()->wallpaper_controller()->AddObserver(this);
+  }
+
+  ~WallpaperShownWaiter() override {
+    Shell::Get()->wallpaper_controller()->RemoveObserver(this);
+  }
+
+  // Note this could only be called once because RunLoop would not run after
+  // Quit is called. Create a new instance if there's need to wait again.
+  void Wait() { run_loop_.Run(); }
+
+ private:
+  // WallpaperControllerObserver:
+  void OnFirstWallpaperShown() override { run_loop_.Quit(); }
+
+  base::RunLoop run_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(WallpaperShownWaiter);
+};
+
 }  // namespace
 
 class ShelfLayoutManagerTest : public AshTestBase {
@@ -986,22 +1009,32 @@ TEST_F(ShelfLayoutManagerTest, AutoHideShelfOnScreenBoundary) {
 // Assertions around the login screen.
 TEST_F(ShelfLayoutManagerTest, VisibleWhenLoginScreenShowing) {
   Shelf* shelf = GetPrimaryShelf();
+  WallpaperController* wallpaper_controller =
+      Shell::Get()->wallpaper_controller();
+  WallpaperShownWaiter waiter;
 
   mojom::SessionInfoPtr info = mojom::SessionInfo::New();
   info->state = session_manager::SessionState::LOGIN_PRIMARY;
-  ash::Shell::Get()->session_controller()->SetSessionInfo(std::move(info));
+  Shell::Get()->session_controller()->SetSessionInfo(std::move(info));
   EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
 
-  // Blurred wallpaper.
-  ash::Shell::Get()->wallpaper_controller()->UpdateWallpaperBlur(/*blur=*/true);
+  // No wallpaper.
+  ASSERT_FALSE(wallpaper_controller->HasShownAnyWallpaper());
   EXPECT_EQ(SHELF_BACKGROUND_LOGIN, GetShelfWidget()->GetBackgroundType());
 
+  // Showing wallpaper is asynchronous.
+  wallpaper_controller->ShowDefaultWallpaperForTesting();
+  waiter.Wait();
+  ASSERT_TRUE(wallpaper_controller->HasShownAnyWallpaper());
+
   // Non-blurred wallpaper.
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      ash::switches::kAshDisableLoginDimAndBlur);
-  ash::Shell::Get()->wallpaper_controller()->UpdateWallpaperBlur(/*blur=*/true);
+  wallpaper_controller->UpdateWallpaperBlur(/*blur=*/false);
   EXPECT_EQ(SHELF_BACKGROUND_LOGIN_NONBLURRED_WALLPAPER,
             GetShelfWidget()->GetBackgroundType());
+
+  // Blurred wallpaper.
+  wallpaper_controller->UpdateWallpaperBlur(/*blur=*/true);
+  EXPECT_EQ(SHELF_BACKGROUND_LOGIN, GetShelfWidget()->GetBackgroundType());
 }
 
 // Assertions around the lock screen showing.

ash/wallpaper/wallpaper_controller.cc

@@ -645,6 +645,10 @@ bool WallpaperController::CanOpenWallpaperPicker() {
          !IsActiveUserWallpaperControlledByPolicyImpl();
 }
 
+bool WallpaperController::HasShownAnyWallpaper() const {
+  return !!current_wallpaper_;
+}
+
 void WallpaperController::ShowWallpaperImage(const gfx::ImageSkia& image,
                                              WallpaperInfo info,
                                              bool preview_mode) {
@@ -686,6 +690,10 @@ void WallpaperController::ShowWallpaperImage(const gfx::ImageSkia& image,
   current_wallpaper_->AddObserver(this);
   current_wallpaper_->StartResize();
 
+  if (is_first_wallpaper_) {
+    for (auto& observer : observers_)
+      observer.OnFirstWallpaperShown();
+  }
   mojo_observers_.ForAllPtrs([this](mojom::WallpaperObserver* observer) {
     observer->OnWallpaperChanged(current_wallpaper_->original_image_id());
   });
@@ -733,6 +741,10 @@ bool WallpaperController::IsBlurAllowed() const {
              switches::kAshDisableLoginDimAndBlur);
 }
 
+bool WallpaperController::IsWallpaperBlurred() const {
+  return is_wallpaper_blurred_;
+}
+
 bool WallpaperController::SetUserWallpaperInfo(const AccountId& account_id,
                                                const WallpaperInfo& info,
                                                bool is_ephemeral) {

ash/wallpaper/wallpaper_controller.h

@@ -148,6 +148,11 @@ class ASH_EXPORT WallpaperController : public mojom::WallpaperController,
   // Returns true if the active user is allowed to open the wallpaper picker.
   bool CanOpenWallpaperPicker();
 
+  // Returns whether any wallpaper has been shown. It returns false before the
+  // first wallpaper is set (which happens momentarily after startup), and will
+  // always return true thereafter.
+  bool HasShownAnyWallpaper() const;
+
   // Shows the wallpaper and alerts observers of changes. Does not show the
   // image if |preview_mode| is false and the current wallpaper is still being
   // previewed. See comments for |confirm_preview_wallpaper_callback_|.
@@ -172,7 +177,9 @@ class ASH_EXPORT WallpaperController : public mojom::WallpaperController,
   bool IsBlurAllowed() const;
 
   // Returns whether the current wallpaper is blurred.
-  bool IsWallpaperBlurred() const { return is_wallpaper_blurred_; }
+  // Note: this returns false when there's no wallpaper yet. Check
+  // |HasShownAnyWallpaper| if there's need to distinguish.
+  bool IsWallpaperBlurred() const;
 
   // Sets wallpaper info for |account_id| and saves it to local state if
   // |is_ephemeral| is false. Returns false if it fails (which happens if local

ash/wallpaper/wallpaper_controller_observer.h

@@ -23,6 +23,10 @@ class ASH_EXPORT WallpaperControllerObserver {
   // Invoked when the wallpaper preview mode ends.
   virtual void OnWallpaperPreviewEnded() {}
 
+  // Invoked when the first wallpaper is set. The first wallpaper is the one
+  // shown right after boot splash screen or after a session restart.
+  virtual void OnFirstWallpaperShown() {}
+
  protected:
   virtual ~WallpaperControllerObserver() {}
 };

ash/wallpaper/wallpaper_controller_unittest.cc

@@ -268,10 +268,15 @@ class TestWallpaperControllerObserver : public WallpaperControllerObserver {
   TestWallpaperControllerObserver() = default;
 
   void OnWallpaperBlurChanged() override { ++wallpaper_blur_changed_count_; }
+  void OnFirstWallpaperShown() override { ++first_wallpaper_shown_count_; }
 
   void Reset() { wallpaper_blur_changed_count_ = 0; }
 
   int wallpaper_blur_changed_count_ = 0;
+  int first_wallpaper_shown_count_ = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestWallpaperControllerObserver);
 };
 
 }  // namespace
@@ -2358,6 +2363,30 @@ TEST_F(WallpaperControllerTest, ShowOneShotWallpaper) {
   EXPECT_EQ(WallpaperType::CUSTOMIZED, controller_->GetWallpaperType());
 }
 
+TEST_F(WallpaperControllerTest, OnFirstWallpaperShown) {
+  TestWallpaperControllerObserver observer;
+  controller_->AddObserver(&observer);
+  EXPECT_EQ(0, GetWallpaperCount());
+  EXPECT_EQ(0, observer.first_wallpaper_shown_count_);
+  // Show the first wallpaper, verify the observer is notified.
+  controller_->ShowWallpaperImage(CreateImage(640, 480, SK_ColorBLUE),
+                                  CreateWallpaperInfo(WALLPAPER_LAYOUT_STRETCH),
+                                  false /*preview_mode=*/);
+  RunAllTasksUntilIdle();
+  EXPECT_EQ(SK_ColorBLUE, GetWallpaperColor());
+  EXPECT_EQ(1, GetWallpaperCount());
+  EXPECT_EQ(1, observer.first_wallpaper_shown_count_);
+  // Show the second wallpaper, verify the observer is not notified.
+  controller_->ShowWallpaperImage(CreateImage(640, 480, SK_ColorCYAN),
+                                  CreateWallpaperInfo(WALLPAPER_LAYOUT_STRETCH),
+                                  false /*preview_mode=*/);
+  RunAllTasksUntilIdle();
+  EXPECT_EQ(SK_ColorCYAN, GetWallpaperColor());
+  EXPECT_EQ(2, GetWallpaperCount());
+  EXPECT_EQ(1, observer.first_wallpaper_shown_count_);
+  controller_->RemoveObserver(&observer);
+}
+
 // A test wallpaper controller client class.
 class TestWallpaperControllerClient : public mojom::WallpaperControllerClient {
  public: