Create accessor for owner's manager to simplify code a bit

content/browser/accessibility/browser_accessibility_com_win.h

Index: content/browser/accessibility/browser_accessibility_com_win.h
diff --git a/content/browser/accessibility/browser_accessibility_com_win.h b/content/browser/accessibility/browser_accessibility_com_win.h
index 32971774b35171aca44825f00ce50874e3f0cb56..5bfac2e0b0b670ed515ae199258c6bc96788dfb6 100644
--- a/content/browser/accessibility/browser_accessibility_com_win.h
+++ b/content/browser/accessibility/browser_accessibility_com_win.h
@@ -745,6 +745,8 @@ class __declspec(uuid("562072fe-3390-43b1-9e2c-dd4118f5ac79"))
   BrowserAccessibilityWin* GetOwner() const { return owner_; }
   void SetOwner(BrowserAccessibilityWin* owner) { owner_ = owner; }
 
+  BrowserAccessibilityManager* Manager() const;
+
   // Returns the IA2 text attributes for this object.
   std::vector<base::string16> ComputeTextAttributes() const;