[headless] Expose DevToolsTarget via HeadlessBrowser + add tracing test.

headless/lib/browser/headless_browser_impl.h

 // Copyright 2015 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 HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_IMPL_H_
 #define HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_IMPL_H_
 
 #include "headless/public/headless_browser.h"
 
 #include <memory>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_contents.h"
 #include "headless/lib/browser/headless_devtools_manager_delegate.h"
 #include "headless/lib/browser/headless_web_contents_impl.h"
 #include "headless/public/headless_export.h"
 
 namespace headless {
 
 class HeadlessBrowserContextImpl;
 class HeadlessBrowserMainParts;
 
 // Exported for tests.
-class HEADLESS_EXPORT HeadlessBrowserImpl : public HeadlessBrowser {
+class HEADLESS_EXPORT HeadlessBrowserImpl : public HeadlessBrowser,
+                                            public HeadlessDevToolsTarget {
  public:
   HeadlessBrowserImpl(
       const base::Callback<void(HeadlessBrowser*)>& on_start_callback,
       HeadlessBrowser::Options options);
   ~HeadlessBrowserImpl() override;
 
   // HeadlessBrowser implementation:
   HeadlessBrowserContext::Builder CreateBrowserContextBuilder() override;
   scoped_refptr<base::SingleThreadTaskRunner> BrowserFileThread()
       const override;
   scoped_refptr<base::SingleThreadTaskRunner> BrowserIOThread() const override;
   scoped_refptr<base::SingleThreadTaskRunner> BrowserMainThread()
       const override;
 
   void Shutdown() override;
 
   std::vector<HeadlessBrowserContext*> GetAllBrowserContexts() override;
   HeadlessWebContents* GetWebContentsForDevToolsAgentHostId(
       const std::string& devtools_agent_host_id) override;
   HeadlessBrowserContext* GetBrowserContextForId(
       const std::string& id) override;
   void SetDefaultBrowserContext(
       HeadlessBrowserContext* browser_context) override;
   HeadlessBrowserContext* GetDefaultBrowserContext() override;
+  HeadlessDevToolsTarget* GetDevToolsTarget() override;
+
+  // HeadlessDevToolsTarget implementation:
+  bool AttachClient(HeadlessDevToolsClient* client) override;
+  void ForceAttachClient(HeadlessDevToolsClient* client) override;
+  void DetachClient(HeadlessDevToolsClient* client) override;
+  bool IsAttached() override;
 
   void set_browser_main_parts(HeadlessBrowserMainParts* browser_main_parts);
   HeadlessBrowserMainParts* browser_main_parts() const;
 
   void RunOnStartCallback();
 
   HeadlessBrowser::Options* options() { return &options_; }
 
   HeadlessBrowserContext* CreateBrowserContext(
       HeadlessBrowserContext::Builder* builder);
@@ skipping 13 matching lines @@
 
  protected:
   base::Callback<void(HeadlessBrowser*)> on_start_callback_;
   HeadlessBrowser::Options options_;
   HeadlessBrowserMainParts* browser_main_parts_;  // Not owned.
 
   std::unordered_map<std::string, std::unique_ptr<HeadlessBrowserContextImpl>>
       browser_contexts_;
   HeadlessBrowserContext* default_browser_context_;  // Not owned.
 
+  scoped_refptr<content::DevToolsAgentHost> agent_host_;
+
   base::WeakPtrFactory<HeadlessBrowserImpl> weak_ptr_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HeadlessBrowserImpl);
 };
 
 }  // namespace headless
 
 #endif  // HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_IMPL_H_