Open system tray in a collapsed state if screen height is limited

Bug: 909101
Change-Id: Ie37bed4e4bee9b5ac2a144cae54f3fc1f63dde28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808493
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699149}

ash/system/unified/unified_system_tray_controller.cc

@@ -103,6 +103,14 @@ UnifiedSystemTrayView* UnifiedSystemTrayController::CreateView() {
       std::make_unique<UnifiedBrightnessSliderController>(model_);
   unified_view_->AddSliderView(brightness_slider_controller_->CreateView());
 
+  // Collapse system tray if there isn't enough space to show notifications when
+  // it is first opened.
+  if (bubble_ && bubble_->CalculateMaxHeight() -
+                         unified_view_->GetExpandedSystemTrayHeight() <
+                     kUnifiedNotificationMinimumHeight) {
+    ResetToCollapsed();
+  }
+
   return unified_view_;
 }
 
@@ -402,6 +410,11 @@ void UnifiedSystemTrayController::UpdateExpandedAmount() {
     model_->set_expanded_on_open(expanded_amount == 1.0);
 }
 
+void UnifiedSystemTrayController::ResetToCollapsed() {
+  unified_view_->SetExpandedAmount(0.0);
+  animation_->Reset(0);
+}
+
 double UnifiedSystemTrayController::GetDragExpandedAmount(
     const gfx::Point& location) const {
   double y_diff = (location - drag_init_point_).y();

ash/system/unified/unified_system_tray_controller.h

@@ -108,6 +108,10 @@ class ASH_EXPORT UnifiedSystemTrayController
   // Ensure the main view is expanded. Called from the slider bubble controller.
   void EnsureExpanded();
 
+  // Collapse the tray without animating. Used to open the tray in a collapsed
+  // state if there is insufficient vertical space.
+  void ResetToCollapsed();
+
   // gfx::AnimationDelegate:
   void AnimationEnded(const gfx::Animation* animation) override;
   void AnimationProgressed(const gfx::Animation* animation) override;