Adds routed interface support between RenderFrameHost and RenderFrame

content/public/browser/web_contents_frame_binding_set.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_FRAME_BINDING_SET_H_
+#define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_FRAME_BINDING_SET_H_
+
+#include "base/macros.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_interface_registry.h"
+
+namespace content {
+
+// A scoper which binds |Interface| to |impl| for every RenderFrameHost
+// belonging to a single WebContents instance.
+template <typename Interface>
+class WebContentsFrameBindingSet {
+ public:
+  explicit WebContentsFrameBindingSet(Interface* impl)
+      : WebContentsFrameBindingSet(nullptr, impl) {}
+
+  WebContentsFrameBindingSet(WebContents* web_contents, Interface* impl)
+      : impl_(impl) {
+    if (web_contents)
+      SetWebContents(web_contents);
+  }
+
+  ~WebContentsFrameBindingSet() {
+    ClearWebContents();
+  }
+
+  void SetWebContents(WebContents* web_contents) {
+    DCHECK(!weak_registry_);
+    WebContentsInterfaceRegistry* registry =
+        web_contents->GetWebContentsInterfaceRegistry();
+    registry->AddFrameInterface<Interface>(impl_);
+    weak_registry_ = registry->GetWeakPtr();
+  }
+
+  void ClearWebContents() {
+    if (weak_registry_) {
+      weak_registry_->RemoveFrameInterface<Interface>();
+      weak_registry_.reset();
+    }
+  }
+
+  // Returns the RenderFrameHost currently targeted by a message dispatch to
+  // the WebContents.
+  RenderFrameHost* GetCurrentTargetFrame() {
+    return weak_registry_->GetCurrentTargetFrame();
+  }
+
+ private:
+  Interface* impl_;
+
+  // We store a WeakPtr to the registry, because some
+  // WebBontentsFrameInterfaceBinding owners may exist as UserData on a
+  // WebContents and therefore outlive the WebContents itself.
+  base::WeakPtr<WebContentsInterfaceRegistry> weak_registry_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsFrameBindingSet);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_FRAME_BINDING_SET_H_