Extend the ToRenderFrameHost magic to FrameTreeNode* and Shell*

content/browser/accessibility/accessibility_ipc_error_browsertest.cc

Index: content/browser/accessibility/accessibility_ipc_error_browsertest.cc
diff --git a/content/browser/accessibility/accessibility_ipc_error_browsertest.cc b/content/browser/accessibility/accessibility_ipc_error_browsertest.cc
index 597631cc2218116d1cf0ba46b1f0fec123d9a610..a89325c22ba4aee2ca4cb89508130fbe49af09a6 100644
--- a/content/browser/accessibility/accessibility_ipc_error_browsertest.cc
+++ b/content/browser/accessibility/accessibility_ipc_error_browsertest.cc
@@ -86,8 +86,7 @@ IN_PROC_BROWSER_TEST_F(AccessibilityIpcErrorBrowserTest,
     AccessibilityNotificationWaiter waiter(
         shell(), AccessibilityModeComplete, ui::AX_EVENT_LIVE_REGION_CHANGED);
     ASSERT_TRUE(ExecuteScript(
-        shell()->web_contents(),
-        "document.getElementById('p1').style.display = 'none';"));
+        shell(), "document.getElementById('p1').style.display = 'none';"));
     waiter.WaitForNotification();
   }
 
@@ -102,9 +101,8 @@ IN_PROC_BROWSER_TEST_F(AccessibilityIpcErrorBrowserTest,
   {
     AccessibilityNotificationWaiter waiter(
         shell(), AccessibilityModeComplete, ui::AX_EVENT_FOCUS);
-    ASSERT_TRUE(ExecuteScript(
-        shell()->web_contents(),
-        "document.getElementById('button').focus();"));
+    ASSERT_TRUE(
+        ExecuteScript(shell(), "document.getElementById('button').focus();"));
     waiter.WaitForNotification();
     tree = &waiter.GetAXTree();
   }