Extend the ToRenderFrameHost magic to FrameTreeNode* and Shell*

content/browser/fileapi/file_system_browsertest.cc

Index: content/browser/fileapi/file_system_browsertest.cc
diff --git a/content/browser/fileapi/file_system_browsertest.cc b/content/browser/fileapi/file_system_browsertest.cc
index 5c60c28f3a8387a7fbca6aa55d8d68df7b54cfb2..ef65b809fac245e3e5022781f0378bf16ec72d9b 100644
--- a/content/browser/fileapi/file_system_browsertest.cc
+++ b/content/browser/fileapi/file_system_browsertest.cc
@@ -45,8 +45,7 @@ class FileSystemBrowserTest : public ContentBrowserTest {
     if (result != "pass") {
       std::string js_result;
       ASSERT_TRUE(ExecuteScriptAndExtractString(
-          the_browser->web_contents(),
-          "window.domAutomationController.send(getLog())",
+          the_browser, "window.domAutomationController.send(getLog())",
           &js_result));
       FAIL() << "Failed: " << js_result;
     }