Revert of Migrate BrowserAccessibility windows unique id handling to AXPlatformNodeWin.

content/browser/accessibility/browser_accessibility.h

Index: content/browser/accessibility/browser_accessibility.h
diff --git a/content/browser/accessibility/browser_accessibility.h b/content/browser/accessibility/browser_accessibility.h
index 7801e01305c198d0504069862c48fa59719d5356..e790989dff6231531790fe84b8e7ff798c08ccbd 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -75,6 +75,8 @@
 
   virtual ~BrowserAccessibility();
 
+  static BrowserAccessibility* GetFromUniqueID(int32_t unique_id);
+
   // Called only once, immediately after construction. The constructor doesn't
   // take any arguments because in the Windows subclass we use a special
   // function to construct a COM object.
@@ -205,6 +207,7 @@
   BrowserAccessibilityManager* manager() const { return manager_; }
   bool instance_active() const { return node_ && manager_; }
   ui::AXNode* node() const { return node_; }
+  int32_t unique_id() const { return unique_id_; }
 
   // These access the internal accessibility tree, which doesn't necessarily
   // reflect the accessibility tree that should be exposed on each platform.