Undocks window first before side-snapping bounds

ash/wm/dock/docked_window_layout_manager.cc

Index: ash/wm/dock/docked_window_layout_manager.cc
diff --git a/ash/wm/dock/docked_window_layout_manager.cc b/ash/wm/dock/docked_window_layout_manager.cc
index f4a2e2629b8225e442dd4d20bfe8a30714acf783..41b5cb55e369ebcfdbb31e665cf66ed22a30bec5 100644
--- a/ash/wm/dock/docked_window_layout_manager.cc
+++ b/ash/wm/dock/docked_window_layout_manager.cc
@@ -101,6 +101,15 @@ void UndockWindow(aura::Window* window) {
   aura::client::ParentWindowWithContext(window, window, gfx::Rect());
   if (window->parent() != previous_parent)
     wm::ReparentTransientChildrenOfChild(window->parent(), window);
+  wm::WindowState* window_state = wm::GetWindowState(window);
+  if (window_state->window_show_type() == wm::SHOW_TYPE_LEFT_SNAPPED ||
+      window_state->window_show_type() == wm::SHOW_TYPE_RIGHT_SNAPPED) {
+    // Windows that are right- or left-snapped out of the dock are have their
+    // bounds already set and the animation started when the undocking happens.
+    // There is no need to reset the layer bounds since correct original bounds
+    // were used for animation.
+    return;
+  }
   // Start maximize or fullscreen (affecting packaged apps) animation from
   // previous window bounds.
   window->layer()->SetBounds(previous_bounds);
@@ -565,11 +574,13 @@ void DockedWindowLayoutManager::OnWindowShowTypeChanged(
     return;
   if (window_state->IsMinimized()) {
     MinimizeDockedWindow(window_state);
-  } else if (window_state->IsMaximizedOrFullscreen()) {
-    // Reparenting changes the source bounds for the animation if a window is
-    // visible so hide it here and show later when it is already in the desktop.
-    UndockWindow(window);
-    RecordUmaAction(DOCKED_ACTION_MAXIMIZE, DOCKED_ACTION_SOURCE_UNKNOWN);
+  } else if (window_state->IsMaximizedOrFullscreen() ||
+      window_state->window_show_type() == wm::SHOW_TYPE_LEFT_SNAPPED ||
+      window_state->window_show_type() == wm::SHOW_TYPE_RIGHT_SNAPPED) {
+    if (window != dragged_window_) {
+      UndockWindow(window);
+      RecordUmaAction(DOCKED_ACTION_MAXIMIZE, DOCKED_ACTION_SOURCE_UNKNOWN);
+    }
   } else if (old_type == wm::SHOW_TYPE_MINIMIZED) {
     RestoreDockedWindow(window_state);
   }