AndroidOverlay implementation using Dialog.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 482e2e3748373d9b0e2880eaa54f9e34c0adf00b..7e553fff7f3d3623b328435a573295edd59b1d29 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -19,6 +19,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "base/strings/string16.h"
 #include "base/supports_user_data.h"
 #include "base/time/time.h"
@@ -134,6 +135,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
   static RenderFrameHostImpl* FromID(int process_id, int routing_id);
   static RenderFrameHostImpl* FromAXTreeID(
       ui::AXTreeIDRegistry::AXTreeID ax_tree_id);
+#if defined(OS_ANDROID)
+  static RenderFrameHostImpl* FromOverlayRoutingToken(
+      const base::UnguessableToken& token);
+#endif
 
   ~RenderFrameHostImpl() override;
 
@@ -634,6 +639,14 @@ class CONTENT_EXPORT RenderFrameHostImpl
 #if defined(OS_ANDROID)
   base::android::ScopedJavaLocalRef<jobject> GetJavaRenderFrameHost();
   service_manager::InterfaceProvider* GetJavaInterfaces() override;
+
+  // Returns an unguessable token for this RFHI.  This provides a temporary way
+  // to identify a RenderFrameHost that's compatible with IPC.  Else, one needs
+  // to send pid + RoutingID, but one cannot send pid.  One can get it from the
+  // channel, but this makes it much harder to get wrong.
+  // Once media switches to mojo, we should be able to remove this in favor of
+  // sending a mojo overlay factory.
+  const base::UnguessableToken& GetOverlayRoutingToken();
 #endif
 
  protected:
@@ -789,6 +802,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
 #endif
 #if defined(OS_ANDROID)
   void OnNavigationHandledByEmbedder();
+
+  // Called when the frame would like an overlay routing token.  This will
+  // create one if needed.  Either way, it will send it to the frame.
+  void OnRequestOverlayRoutingToken();
 #endif
   void OnShowCreatedWindow(int pending_widget_routing_id,
                            WindowOpenDisposition disposition,
@@ -1171,6 +1188,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
 
 #if defined(OS_ANDROID)
   std::unique_ptr<service_manager::InterfaceProvider> java_interfaces_;
+
+  // IPC-friendly token that represents this host for AndroidOverlays, if we
+  // have created one yet.
+  base::Optional<base::UnguessableToken> overlay_routing_token_;
 #endif
 
   // NOTE: This must be the last member.