[VK] Remove outdated comment in OnWindowBoundsChanged.

This comment is outdated: this is no longer true for other container
behaviours.

TBR=blakeo@chromium.org

Change-Id: I8cd3bce943f4e177d41ad404eb7fb737a0dd397f
Reviewed-on: https://chromium-review.googlesource.com/1113713Reviewed-by: Darren Shen <shend@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570344}

ui/keyboard/keyboard_controller.cc

@@ -531,11 +531,7 @@ void KeyboardController::OnWindowBoundsChanged(
     const gfx::Rect& old_bounds,
     const gfx::Rect& new_bounds,
     ui::PropertyChangeReason reason) {
-  if (!window->IsRootWindow())
-    return;
-  // Keep the same height when window resizes. It gets called when the screen
-  // rotates.
-  if (!ui_->HasContentsWindow())
+  if (!window->IsRootWindow() || !ui_->HasContentsWindow())
     return;
 
   container_behavior_->SetCanonicalBounds(GetContentsWindow(), new_bounds);