Fix virtual keyboard overscroll on Athena

This CL:
- Removes GetFrameWindow() from KeyboardController because the function is not
  compatible with Athena
- Avoids showing the keyboard container after creating it. This was causing
  the insets not to be set on the RenderWidgetHostViews the first time that the
  keyboard is shown

BUG=431798
TEST=None

Review URL: https://codereview.chromium.org/711243004

Cr-Commit-Position: refs/heads/master@{#303888}

1 files changed, 0 insertions, 1 deletions

diff --git a/athena/virtual_keyboard/virtual_keyboard_manager_impl.cc b/athena/virtual_keyboard/virtual_keyboard_manager_impl.cc
index abb0b3f..1d5e77d 100644
--- a/athena/virtual_keyboard/virtual_keyboard_manager_impl.cc
+++ b/athena/virtual_keyboard/virtual_keyboard_manager_impl.cc
@@ -90,7 +90,6 @@ class VirtualKeyboardManagerImpl : public VirtualKeyboardManager {
     aura::Window* kb_container = controller->GetContainerWindow();
     FillLayoutManager::SetAlwaysFill(kb_container);
     container_->AddChild(kb_container);
-    kb_container->Show();
   }
 
   content::BrowserContext* browser_context_;