binding: Calls didAccessInitialDocument() for a returned Window.

third_party/WebKit/Source/core/frame/DOMWindow.cpp

Index: third_party/WebKit/Source/core/frame/DOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMWindow.cpp b/third_party/WebKit/Source/core/frame/DOMWindow.cpp
index 3d1f12c7efdbb84f6907c18c4ecbfee3775d98b8..914aa05bd5397eeaed884cfeda28206e4d7e4ba2 100644
--- a/third_party/WebKit/Source/core/frame/DOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMWindow.cpp
@@ -130,8 +130,22 @@ DOMWindow* DOMWindow::anonymousIndexedGetter(uint32_t index) const
     if (!frame())
         return nullptr;
 
-    Frame* child = frame()->tree().scopedChild(index);
-    return child ? child->domWindow() : nullptr;
+    Frame* childFrame = frame()->tree().scopedChild(index);
+    if (!childFrame)
+        return nullptr;
+
+    DOMWindow* childWindow = childFrame->domWindow();
+    if (childWindow && childWindow->isLocalDOMWindow()) {
+        LocalFrame* targetFrame = blink::toLocalDOMWindow(childWindow)->frame();
+        if (targetFrame) {
+            // Notify the loader's client if the initial document has been accessed.
+            if (targetFrame->loader().stateMachine()->isDisplayingInitialEmptyDocument()) {
+                targetFrame->loader().didAccessInitialDocument();
+            }
+        }
+    }
+
+    return childWindow;
 }
 
 bool DOMWindow::isCurrentlyDisplayedInFrame() const