Create only a single LegacyRenderWidgetHostHWND per WebContentsViewAura.

content/browser/accessibility/browser_accessibility_manager_win.cc

Index: content/browser/accessibility/browser_accessibility_manager_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_manager_win.cc b/content/browser/accessibility/browser_accessibility_manager_win.cc
index 05e2fd507e8c73f420260a6afdd5fb419948c956..aafba06118e6ab4cd59d653615a984830953418e 100644
--- a/content/browser/accessibility/browser_accessibility_manager_win.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_win.cc
@@ -21,8 +21,7 @@ BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManagerWin(
-      content::LegacyRenderWidgetHostHWND::Create(GetDesktopWindow()),
-      NULL, initial_tree, delegate, factory);
+      NULL, NULL, initial_tree, delegate, factory);
 }
 
 BrowserAccessibilityManagerWin*
@@ -43,10 +42,9 @@ BrowserAccessibilityManagerWin::BrowserAccessibilityManagerWin(
       accessible_hwnd_(accessible_hwnd),
       focus_event_on_root_needed_(false) {
   ui::win::CreateATLModuleIfNeeded();
-  if (accessible_hwnd_) {
-    accessible_hwnd_->set_browser_accessibility_manager(this);
-    parent_hwnd_ = accessible_hwnd_->GetParent();
-  }
+  if (!accessible_hwnd_)
+    accessible_hwnd_ = LegacyRenderWidgetHostHWND::CreateForTesting(this);
+  parent_hwnd_ = accessible_hwnd_->GetParent();
 }
 
 BrowserAccessibilityManagerWin::~BrowserAccessibilityManagerWin() {
@@ -54,8 +52,6 @@ BrowserAccessibilityManagerWin::~BrowserAccessibilityManagerWin() {
     tracked_scroll_object_->Release();
     tracked_scroll_object_ = NULL;
   }
-  if (accessible_hwnd_)
-    accessible_hwnd_->OnManagerDeleted(this);
 }
 
 // static
@@ -73,19 +69,6 @@ ui::AXTreeUpdate BrowserAccessibilityManagerWin::GetEmptyDocument() {
   return update;
 }
 
-void BrowserAccessibilityManagerWin::SetAccessibleHWND(
-    LegacyRenderWidgetHostHWND* accessible_hwnd) {
-  if (accessible_hwnd_)
-    accessible_hwnd_->OnManagerDeleted(this);
-
-  accessible_hwnd_ = accessible_hwnd;
-
-  if (accessible_hwnd_) {
-    accessible_hwnd_->set_browser_accessibility_manager(this);
-    parent_hwnd_ = accessible_hwnd_->GetParent();
-  }
-}
-
 void BrowserAccessibilityManagerWin::MaybeCallNotifyWinEvent(DWORD event,
                                                              LONG child_id) {
   // If on Win 7 and complete accessibility is enabled, use the fake child HWND