Migrate BrowserAccessibility windows unique id handling to AXPlatformNodeWin.

content/browser/accessibility/browser_accessibility_android.h

Index: content/browser/accessibility/browser_accessibility_android.h
diff --git a/content/browser/accessibility/browser_accessibility_android.h b/content/browser/accessibility/browser_accessibility_android.h
index d9e5ad05e3a05345cd1e68d760b42e89250e290f..823a18c712e28a6e0a5a680215c456ac7dc5df02 100644
--- a/content/browser/accessibility/browser_accessibility_android.h
+++ b/content/browser/accessibility/browser_accessibility_android.h
@@ -11,11 +11,15 @@
 #include "base/android/scoped_java_ref.h"
 #include "base/macros.h"
 #include "content/browser/accessibility/browser_accessibility.h"
+#include "ui/accessibility/platform/ax_platform_node.h"
 
 namespace content {
 
 class CONTENT_EXPORT BrowserAccessibilityAndroid : public BrowserAccessibility {
  public:
+  static BrowserAccessibilityAndroid* GetFromUniqueId(int32_t unique_id);
+  int32_t unique_id() const { return unique_id_; }
+
   // Overrides from BrowserAccessibility.
   void OnDataChanged() override;
   bool IsNative() const override;
@@ -137,6 +141,7 @@ class CONTENT_EXPORT BrowserAccessibilityAndroid : public BrowserAccessibility {
   friend class BrowserAccessibility;
 
   BrowserAccessibilityAndroid();
+  ~BrowserAccessibilityAndroid() override;
 
   bool HasOnlyTextChildren() const;
   bool HasOnlyTextAndImageChildren() const;
@@ -157,6 +162,7 @@ class CONTENT_EXPORT BrowserAccessibilityAndroid : public BrowserAccessibility {
   bool first_time_;
   base::string16 old_value_;
   base::string16 new_value_;
+  int32_t unique_id_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityAndroid);
 };