Add a function to send scripts from a browsertest to an extension's background page.

chrome/browser/extensions/extension_browsertest.cc

Index: chrome/browser/extensions/extension_browsertest.cc
diff --git a/chrome/browser/extensions/extension_browsertest.cc b/chrome/browser/extensions/extension_browsertest.cc
index 5e9ec68b0e9db714f3f4ba20cf9b557fcdc5b376..371554e5bb2e404cf2f478e3c1d837994190bb14 100644
--- a/chrome/browser/extensions/extension_browsertest.cc
+++ b/chrome/browser/extensions/extension_browsertest.cc
@@ -15,6 +15,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/extensions/browsertest_util.h"
 #include "chrome/browser/extensions/component_loader.h"
 #include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/extension_creator.h"
@@ -676,6 +677,13 @@ extensions::ExtensionHost* ExtensionBrowserTest::FindHostWithPath(
   return host;
 }
 
+std::string ExtensionBrowserTest::ExecuteScriptInBackgroundPage(
+    const std::string& extension_id,
+    const std::string& script) {
+  return extensions::browsertest_util::ExecuteScriptInBackgroundPage(
+      profile(), extension_id, script);
+}
+
 void ExtensionBrowserTest::Observe(
     int type,
     const content::NotificationSource& source,