If the user autohid the shelf, the shelf currently momentarily reveals when transitioning out of fullscreen.

The reason is that there are temporarily no visible windows which causes ShelfLayoutManager::CalculateAutoHideState() to return SHELF_AUTO_HIDE_SHOWN.

In particular, the following code in workspace_manager.cc causes this behavior:
ReparentWindow(child, desktop_workspace()->window(), NULL);
SetActiveWorkspace(desktop_workspace(), SWITCH_MAXIMIZED_OR_RESTORED, duration);

BUG=250918
TEST=Manual, see bug

Review URL: https://chromiumcodereview.appspot.com/16959021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@209648 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 33 insertions, 2 deletions

diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index 9a6b912..c53da27 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -581,7 +581,6 @@ void ShelfLayoutManager::SetState(ShelfVisibilityState visibility_state) {
        state_.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN &&
        state.visibility_state == SHELF_VISIBLE) ?
       BackgroundAnimator::CHANGE_IMMEDIATE : BackgroundAnimator::CHANGE_ANIMATE;
-  StopAnimating();
 
   State old_state = state_;
   state_ = state;
@@ -593,6 +592,8 @@ void ShelfLayoutManager::SetState(ShelfVisibilityState visibility_state) {
   launcher_animation_setter.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(kWorkspaceSwitchTimeMS));
   launcher_animation_setter.SetTweenType(ui::Tween::EASE_OUT);
+  launcher_animation_setter.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
   GetLayer(shelf_)->SetBounds(
       target_bounds.shelf_bounds_in_root);
   GetLayer(shelf_)->SetOpacity(target_bounds.opacity);
@@ -601,6 +602,8 @@ void ShelfLayoutManager::SetState(ShelfVisibilityState visibility_state) {
   status_animation_setter.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(kWorkspaceSwitchTimeMS));
   status_animation_setter.SetTweenType(ui::Tween::EASE_OUT);
+  status_animation_setter.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
 
   // Delay updating the background when going from SHELF_AUTO_HIDE_SHOWN to
   // SHELF_AUTO_HIDE_HIDDEN until the shelf animates out. Otherwise during the
diff --git a/ash/shelf/shelf_layout_manager.h b/ash/shelf/shelf_layout_manager.h
index f113675..d49f42a 100644
--- a/ash/shelf/shelf_layout_manager.h
+++ b/ash/shelf/shelf_layout_manager.h
@@ -238,7 +238,7 @@ class ASH_EXPORT ShelfLayoutManager :
   // Sets the visibility of the shelf to |state|.
   void SetState(ShelfVisibilityState visibility_state);
 
-  // Stops any animations.
+  // Stops any animations and progresses them to the end.
   void StopAnimating();
 
   // Returns the width (if aligned to the side) or height (if aligned to the
diff --git a/ash/shelf/shelf_layout_manager_unittest.cc b/ash/shelf/shelf_layout_manager_unittest.cc
index a0db945..20b5be0 100644
--- a/ash/shelf/shelf_layout_manager_unittest.cc
+++ b/ash/shelf/shelf_layout_manager_unittest.cc
@@ -33,6 +33,7 @@
 #include "ui/base/animation/animation_container_element.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animator.h"
+#include "ui/compositor/scoped_animation_duration_scale_mode.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/controls/label.h"
@@ -659,6 +660,33 @@ TEST_F(ShelfLayoutManagerTest, LayoutShelfWhileAnimating) {
             Shell::GetScreen()->GetPrimaryDisplay().bounds().bottom());
 }
 
+// Test that switching to a different visibility state does not restart the
+// shelf show / hide animation if it is already running. (crbug.com/250918)
+TEST_F(ShelfLayoutManagerTest, SetStateWhileAnimating) {
+  ShelfWidget* shelf = GetShelfWidget();
+  SetState(shelf->shelf_layout_manager(), SHELF_VISIBLE);
+  gfx::Rect initial_shelf_bounds = shelf->GetWindowBoundsInScreen();
+  gfx::Rect initial_status_bounds =
+      shelf->status_area_widget()->GetWindowBoundsInScreen();
+
+  ui::ScopedAnimationDurationScaleMode normal_animation_duration(
+      ui::ScopedAnimationDurationScaleMode::SLOW_DURATION);
+  SetState(shelf->shelf_layout_manager(), SHELF_HIDDEN);
+  SetState(shelf->shelf_layout_manager(), SHELF_VISIBLE);
+
+  gfx::Rect current_shelf_bounds = shelf->GetWindowBoundsInScreen();
+  gfx::Rect current_status_bounds =
+      shelf->status_area_widget()->GetWindowBoundsInScreen();
+
+  const int small_change = initial_shelf_bounds.height() / 2;
+  EXPECT_LE(
+      std::abs(initial_shelf_bounds.height() - current_shelf_bounds.height()),
+      small_change);
+  EXPECT_LE(
+      std::abs(initial_status_bounds.height() - current_status_bounds.height()),
+      small_change);
+}
+
 // Makes sure the launcher is sized when the status area changes size.
 TEST_F(ShelfLayoutManagerTest, LauncherUpdatedWhenStatusAreaChangesSize) {
   Launcher* launcher = Launcher::ForPrimaryDisplay();