Create only a single LegacyRenderWidgetHostHWND per WebContentsViewAura.

content/browser/web_contents/web_contents_view_aura.h

Index: content/browser/web_contents/web_contents_view_aura.h
diff --git a/content/browser/web_contents/web_contents_view_aura.h b/content/browser/web_contents/web_contents_view_aura.h
index 05fe1b092d1d805297f9147b2b58e7a0d6d08a56..977540a144fc2e1e2236ec2a7671bf66e9618fd3 100644
--- a/content/browser/web_contents/web_contents_view_aura.h
+++ b/content/browser/web_contents/web_contents_view_aura.h
@@ -19,6 +19,11 @@
 #include "ui/aura/window_observer.h"
 #include "ui/wm/public/drag_drop_delegate.h"
 
+#if defined(OS_WIN)
+#include "content/browser/renderer_host/legacy_render_widget_host_win.h"
+#include "content/browser/renderer_host/legacy_render_widget_host_win_delegate.h"
+#endif
+
 namespace aura {
 class Window;
 }
@@ -39,8 +44,15 @@ class WebContentsViewDelegate;
 class WebContentsImpl;
 class WebDragDestDelegate;
 
+#if defined(OS_WIN)
+class LegacyRenderWidgetHostHWND;
+#endif
+
 class CONTENT_EXPORT WebContentsViewAura
     : NON_EXPORTED_BASE(public WebContentsView),
+#if defined(OS_WIN)
+      public LegacyRenderWidgetHostHWNDDelegate,
+#endif
       public RenderViewHostDelegateView,
       public OverscrollControllerDelegate,
       public aura::WindowDelegate,
@@ -156,6 +168,11 @@ class CONTENT_EXPORT WebContentsViewAura
 
   FRIEND_TEST_ALL_PREFIXES(WebContentsViewAuraTest, EnableDisableOverscroll);
 
+#if defined(OS_WIN)
+  // Overridden from LegacyRenderWidgetHostHWNDDelegate:
+  gfx::NativeViewAccessible GetNativeViewAccessible() override;
+#endif
+
   std::unique_ptr<aura::Window> window_;
 
   std::unique_ptr<WindowObserver> window_observer_;
@@ -190,6 +207,18 @@ class CONTENT_EXPORT WebContentsViewAura
 
   std::unique_ptr<GestureNavSimple> gesture_nav_simple_;
 
+#if defined(OS_WIN)
+  // The LegacyRenderWidgetHostHWND class provides a dummy HWND which is used
+  // for accessibility, as the container for windowless plugins like
+  // Flash/Silverlight, etc and for legacy drivers for trackpoints/trackpads,
+  // etc.
+  std::unique_ptr<LegacyRenderWidgetHostHWND> legacy_hwnd_;
+#endif
+
+  // On Windows we can run into problems if resources get released within the
+  // initialization phase while the content (and its dimensions) are not known.
+  bool is_or_was_visible_;
+
   DISALLOW_COPY_AND_ASSIGN(WebContentsViewAura);
 };