When we switch tabs in chrome, the tab being switched away from gets hidden/shown/hidden.

ui/views/controls/webview/webview.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/webview/webview.h"
 
 #include "content/public/browser/browser_accessibility_state.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "ipc/ipc_message.h"
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_view_state.h"
+#include "ui/aura/window.h"
 #include "ui/base/ui_base_switches_util.h"
 #include "ui/events/event.h"
 #include "ui/views/accessibility/native_view_accessibility.h"
 #include "ui/views/controls/native/native_view_host.h"
 #include "ui/views/focus/focus_manager.h"
 #include "ui/views/views_delegate.h"
 
 namespace views {
 
 // static
@@ skipping 268 matching lines @@
   // already attached.
   if (!GetWidget() || !web_contents())
     return;
 
   const gfx::NativeView view_to_attach = is_embedding_fullscreen_widget_ ?
       web_contents()->GetFullscreenRenderWidgetHostView()->GetNativeView() :
       web_contents()->GetNativeView();
   OnBoundsChanged(bounds());
   if (holder_->native_view() == view_to_attach)
     return;
+
+  // Fullscreen widgets are not parented by a WebContentsView. Their visibility
+  // is controlled by content i.e. (RenderWidgetHost)
+  if (!is_embedding_fullscreen_widget_)
+    view_to_attach->Show();
+
   holder_->Attach(view_to_attach);
 
   // The view will not be focused automatically when it is attached, so we need
   // to pass on focus to it if the FocusManager thinks the view is focused. Note
   // that not every Widget has a focus manager.
   FocusManager* const focus_manager = GetFocusManager();
   if (focus_manager && focus_manager->GetFocusedView() == this)
     OnFocus();
 
 #if defined(OS_WIN)
   if (!is_embedding_fullscreen_widget_) {
     web_contents()->SetParentNativeViewAccessible(
         parent()->GetNativeViewAccessible());
   }
 #endif
 }
 
 void WebView::DetachWebContents() {
   if (web_contents()) {
+    // Fullscreen widgets are not parented by a WebContentsView. Their
+    // visibility is controlled by content i.e. (RenderWidgetHost).
+    if (!is_embedding_fullscreen_widget_)
+      web_contents()->GetNativeView()->Hide();
+
     holder_->Detach();
 #if defined(OS_WIN)
     if (!is_embedding_fullscreen_widget_)
       web_contents()->SetParentNativeViewAccessible(NULL);
 #endif
   }
 }
 
 void WebView::ReattachForFullscreenChange(bool enter_fullscreen) {
   DCHECK(embed_fullscreen_widget_mode_enabled_);
@@ skipping 32 matching lines @@
   if (!contents) {
     content::WebContents::CreateParams create_params(
         browser_context, NULL);
     return content::WebContents::Create(create_params);
   }
 
   return contents;
 }
 
 }  // namespace views