Move GetDocument method from WebFrame to WebLocalFrame.

extensions/renderer/api/automation/automation_api_helper.cc

Index: extensions/renderer/api/automation/automation_api_helper.cc
diff --git a/extensions/renderer/api/automation/automation_api_helper.cc b/extensions/renderer/api/automation/automation_api_helper.cc
index 45c62026f263d18b390e2e183fbcc35dedfefbeb..bcb4ad86f1baf6e488a25dd49e8a77853bcbe23f 100644
--- a/extensions/renderer/api/automation/automation_api_helper.cc
+++ b/extensions/renderer/api/automation/automation_api_helper.cc
@@ -10,7 +10,7 @@
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebExceptionCode.h"
-#include "third_party/WebKit/public/web/WebFrame.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebNode.h"
 #include "third_party/WebKit/public/web/WebView.h"
 
@@ -47,8 +47,15 @@ void AutomationApiHelper::OnQuerySelector(int request_id,
         routing_id(), request_id, error, 0));
     return;
   }
-  blink::WebDocument document =
-      render_view()->GetWebView()->MainFrame()->GetDocument();
+
+  // ExtensionMsg_AutomationQuerySelector should only be sent to an active view.
+  DCHECK(render_view()->GetWebView()->MainFrame()->IsWebLocalFrame());
+
+  blink::WebDocument document = render_view()
+                                    ->GetWebView()
+                                    ->MainFrame()
+                                    ->ToWebLocalFrame()
+                                    ->GetDocument();
   if (document.IsNull()) {
     error.value = ExtensionHostMsg_AutomationQuerySelector_Error::kNoDocument;
     Send(new ExtensionHostMsg_AutomationQuerySelector_Result(