[DevTools] Move DevToolsClientHost functionality out of DevToolsFrontendHost.

content/public/browser/devtools_frontend_host.h

+// Copyright (c) 2012 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_DEVTOOLS_FRONTEND_HOST_H_
+#define CONTENT_PUBLIC_BROWSER_DEVTOOLS_FRONTEND_HOST_H_
+
+#include <string>
+
+#include "content/common/content_export.h"
+#include "url/gurl.h"
+
+namespace content {
+
+class WebContents;
+
+// This class dispatches messages between DevTools frontend and Delegate
+// which is implemented by the embedder.
+// This allows us to avoid exposing DevTools frontend messages through
+// the content public API.
+class DevToolsFrontendHost {
+ public:
+  // Delegate actually handles messages from frontend.
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // When navigation happens in DevTools frontend WebContents, delegate
+    // decides on whether new page is DevTools frontend.
+    virtual bool ShouldSetupDevToolsFrontendForUrl(const GURL& url) = 0;
+
+    // Message is coming from frontend to the embedder.
+    virtual void HandleMessageFromDevToolsFrontend(
+        const std::string& message) = 0;
+
+    // Message is coming from frontend to the backend.
+    // TODO(dgozman): make this to be one of the possible messages to embedder.
+    virtual void HandleMessageFromDevToolsFrontendToBackend(
+        const std::string& message) = 0;
+  };
+
+  // Creates a new DevToolsFrontendHost for WebContents where DevTools
+  // frontend is loaded.
+  CONTENT_EXPORT static DevToolsFrontendHost* Create(
+      WebContents* frontend_web_contents, Delegate* delegate);
+
+  CONTENT_EXPORT virtual ~DevToolsFrontendHost() {}
+
+  // Dispatches message from embedder/backend to frontend.
+  // TODO(dgozman): remove and make embedder to take care of this.
+  CONTENT_EXPORT virtual void DispatchOnDevToolsFrontend(
+      const std::string& message) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_DEVTOOLS_FRONTEND_HOST_H_