[DevTools] New harness for inspector-protocol layout tests

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 db7bd746debc2adb5b5a09ace4584d117497e682..e58d69a83a31e3b250e19d92491118bea9e9f0a6 100644
--- a/content/shell/browser/shell_devtools_manager_delegate.cc
+++ b/content/shell/browser/shell_devtools_manager_delegate.cc
@@ -28,8 +28,10 @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/user_agent.h"
+#include "content/shell/browser/layout_test/secondary_test_window_observer.h"
 #include "content/shell/browser/shell.h"
 #include "content/shell/common/shell_content_client.h"
+#include "content/shell/common/shell_switches.h"
 #include "content/shell/grit/shell_resources.h"
 #include "net/base/net_errors.h"
 #include "net/log/net_log_source.h"
@@ -193,6 +195,8 @@ ShellDevToolsManagerDelegate::CreateNewTarget(const GURL& url) {
                                         url,
                                         nullptr,
                                         gfx::Size());
+  if (switches::IsRunLayoutTestSwitchPresent())
+    SecondaryTestWindowObserver::CreateForWebContents(shell->web_contents());
   return DevToolsAgentHost::GetOrCreateFor(shell->web_contents());
 }