Introduce RenderFrameVisitor

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 4b25c97a1395c02efaa633f8b1ff34ff6d6eb48f..8c797b53859e3ea3d827edaececaf9c4f658986b 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -90,6 +90,7 @@
 #include "content/public/renderer/document_state.h"
 #include "content/public/renderer/navigation_state.h"
 #include "content/public/renderer/render_frame_observer.h"
+#include "content/public/renderer/render_frame_visitor.h"
 #include "content/public/renderer/renderer_ppapi_host.h"
 #include "content/renderer/accessibility/render_accessibility_impl.h"
 #include "content/renderer/browser_plugin/browser_plugin.h"
@@ -1051,6 +1052,15 @@ RenderFrame* RenderFrame::FromWebFrame(blink::WebFrame* web_frame) {
 }
 
 // static
+void RenderFrame::ForEach(RenderFrameVisitor* visitor) {
+  FrameMap* frames = g_frame_map.Pointer();
+  for (FrameMap::iterator it = frames->begin(); it != frames->end(); ++it) {
+    if (!visitor->Visit(it->second))
+      return;
+  }
+}
+
+// static
 RenderFrameImpl* RenderFrameImpl::FromWebFrame(blink::WebFrame* web_frame) {
   FrameMap::iterator iter = g_frame_map.Get().find(web_frame);
   if (iter != g_frame_map.Get().end())