Update work area insets when a11y panel height changes

BUG=1101315

Change-Id: I650582530cb48a209b489777325f672714bec041
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2284149Reviewed-by: Katie Dektar <katie@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786341}

ash/accessibility/accessibility_panel_layout_manager.cc

@@ -137,15 +137,18 @@ void AccessibilityPanelLayoutManager::UpdateWindowBounds() {
     bounds.set_height(available_height);
 
   panel_window_->SetBounds(bounds);
+
+  UpdateWorkAreaForPanelHeight();
 }
 
 void AccessibilityPanelLayoutManager::UpdateWorkAreaForPanelHeight() {
   bool has_height = panel_window_ && panel_window_->bounds().y() == 0 &&
                     panel_state_ == AccessibilityPanelState::FULL_WIDTH;
-  Shell::GetPrimaryRootWindowController()
-      ->work_area_insets()
-      ->SetAccessibilityPanelHeight(
-          has_height ? panel_window_->bounds().height() : 0);
+  const int height = has_height ? panel_window_->bounds().height() : 0;
+  WorkAreaInsets* const work_area_insets =
+      Shell::GetPrimaryRootWindowController()->work_area_insets();
+  if (work_area_insets->accessibility_panel_height() != height)
+    work_area_insets->SetAccessibilityPanelHeight(height);
 }
 
 }  // namespace ash