DevTools: merge devtools_http_handler into content - it is used in all the embedders anyways.

headless/lib/browser/headless_devtools_manager_delegate.h

Index: headless/lib/browser/headless_devtools_manager_delegate.h
diff --git a/headless/lib/browser/headless_devtools_manager_delegate.h b/headless/lib/browser/headless_devtools_manager_delegate.h
index 52dd17393759c8a65bc373cb843fdd437e51b0b1..088c247e5c95197b6a994c6772e0ce46bfc69bd6 100644
--- a/headless/lib/browser/headless_devtools_manager_delegate.h
+++ b/headless/lib/browser/headless_devtools_manager_delegate.h
@@ -32,10 +32,8 @@ class HeadlessDevToolsManagerDelegate
                                  bool attached) override{};
   base::DictionaryValue* HandleCommand(content::DevToolsAgentHost* agent_host,
                                        base::DictionaryValue* command) override;
-  std::string GetTargetType(content::RenderFrameHost* host) override;
-  std::string GetTargetTitle(content::RenderFrameHost* host) override;
-  scoped_refptr<content::DevToolsAgentHost> CreateNewTarget(
-      const GURL& url) override;
+  std::string GetDiscoveryPageHTML() override;
+  std::string GetFrontendResource(const std::string& path) override;
 
  private:
   std::unique_ptr<base::Value> CreateTarget(