Use unique IDs for accessibility nodes on Android

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 edef50d8a9f80d73e7c36b040e30b57cefb6a4d9..b2f14f9877bb53be9e2669e2b01ebc5c7b13287d 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -75,6 +75,8 @@ class CONTENT_EXPORT BrowserAccessibility {
 
   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.
@@ -194,6 +196,7 @@ class CONTENT_EXPORT BrowserAccessibility {
   BrowserAccessibilityManager* manager() const { return manager_; }
   bool instance_active() const { return node_ != NULL; }
   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.
@@ -220,17 +223,6 @@ class CONTENT_EXPORT BrowserAccessibility {
   // IsNative returns false.
   virtual bool IsNative() const;
 
-#if defined(OS_MACOSX) && __OBJC__
-  const BrowserAccessibilityCocoa* ToBrowserAccessibilityCocoa() const;
-  BrowserAccessibilityCocoa* ToBrowserAccessibilityCocoa();
-#elif defined(OS_WIN)
-  const BrowserAccessibilityWin* ToBrowserAccessibilityWin() const;
-  BrowserAccessibilityWin* ToBrowserAccessibilityWin();
-#elif defined(OS_LINUX) && !defined(OS_CHROMEOS) && defined(USE_X11)
-  const BrowserAccessibilityAuraLinux* ToBrowserAccessibilityAuraLinux() const;
-  BrowserAccessibilityAuraLinux* ToBrowserAccessibilityAuraLinux();
-#endif
-
   // Accessing accessibility attributes:
   //
   // There are dozens of possible attributes for an accessibility node,
@@ -328,6 +320,9 @@ class CONTENT_EXPORT BrowserAccessibility {
   // The underlying node.
   ui::AXNode* node_;
 
+  // A unique ID, since node IDs are frame-local.
+  int32_t unique_id_;
+
  private:
   // |GetInnerText| recursively includes all the text from descendants such as
   // text found in any embedded object. In contrast, |GetText| might include a