DevTools: reuse ephemeral port from http handler in the shell front-end.

content/shell/browser/shell_devtools_manager_delegate.cc

Index: content/shell/browser/shell_devtools_manager_delegate.cc
diff --git a/content/shell/browser/shell_devtools_manager_delegate.cc b/content/shell/browser/shell_devtools_manager_delegate.cc
index 526ad376b145bc421c032cbfbc8cd14f94bf7f72..47c5b2dbe53f1027e799633ea5aef177c31b9bc1 100644
--- a/content/shell/browser/shell_devtools_manager_delegate.cc
+++ b/content/shell/browser/shell_devtools_manager_delegate.cc
@@ -8,6 +8,7 @@
 
 #include <vector>
 
+#include "base/atomicops.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ -51,6 +52,8 @@ const char kFrontEndURL[] =
 
 const int kBackLog = 10;
 
+base::subtle::Atomic32 g_last_used_port;
+
 #if defined(OS_ANDROID)
 class UnixDomainServerSocketFactory : public content::DevToolsSocketFactory {
  public:
@@ -92,6 +95,10 @@ class TCPServerSocketFactory : public content::DevToolsSocketFactory {
     if (socket->ListenWithAddressAndPort(address_, port_, kBackLog) != net::OK)
       return std::unique_ptr<net::ServerSocket>();
 
+    net::IPEndPoint endpoint;
+    if (socket->GetLocalAddress(&endpoint) == net::OK)
+      base::subtle::NoBarrier_Store(&g_last_used_port, endpoint.port());
+
     return socket;
   }
 
@@ -143,6 +150,11 @@ std::unique_ptr<content::DevToolsSocketFactory> CreateSocketFactory() {
 // ShellDevToolsManagerDelegate ----------------------------------------------
 
 // static
+int ShellDevToolsManagerDelegate::GetHttpHandlerPort() {
+  return base::subtle::NoBarrier_Load(&g_last_used_port);
+}
+
+// static
 void ShellDevToolsManagerDelegate::StartHttpHandler(
     BrowserContext* browser_context) {
   std::string frontend_url;