Implement WebContentsViewChildFrame::TakeFocus.

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 127c0229fbef6ab533d8e208fad9befe6eb85a1b..ce3d714cc2d785f1961f6400395b1532c8c0f10d 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -40,6 +40,7 @@
 #include "net/http/http_response_headers.h"
 #include "services/service_manager/public/cpp/interface_factory.h"
 #include "services/service_manager/public/cpp/interface_registry.h"
+#include "third_party/WebKit/public/platform/WebFocusType.h"
 #include "third_party/WebKit/public/platform/WebInsecureRequestPolicy.h"
 #include "third_party/WebKit/public/web/WebTextDirection.h"
 #include "third_party/WebKit/public/web/WebTreeScopeType.h"
@@ -427,6 +428,12 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // cross-process window.focus() calls.
   void SetFocusedFrame();
 
+  // Continues sequential focus navigation in this frame. |source_proxy|
+  // represents the frame that requested a focus change. It must be in the same
+  // process as this or |nullptr|.
+  void AdvanceFocus(blink::WebFocusType type,
+                    RenderFrameProxyHost* source_proxy);
+
   // Deletes the current selection plus the specified number of characters
   // before and after the selection or caret.
   void ExtendSelectionAndDelete(size_t before, size_t after);