Fix keyboard focus for OOPIF-<webview>.

content/public/test/browser_test_utils.h

Index: content/public/test/browser_test_utils.h
diff --git a/content/public/test/browser_test_utils.h b/content/public/test/browser_test_utils.h
index 52f48f18fd7330fcf6c6a9f155c2288064e05d9c..891d40bc183c1365df08be859677b5913bd90944 100644
--- a/content/public/test/browser_test_utils.h
+++ b/content/public/test/browser_test_utils.h
@@ -574,6 +574,24 @@ class BrowserTestClipboardScope {
   DISALLOW_COPY_AND_ASSIGN(BrowserTestClipboardScope);
 };
 
+// This observer is used to wait for its owner Frame to become focused.
+class FrameFocusedObserver {
+  // Private impl struct which hides non public types including FrameTreeNode.
+  class FrameTreeNodeObserverImpl;
+
+ public:
+  explicit FrameFocusedObserver(RenderFrameHost* owner_host);
+  ~FrameFocusedObserver();
+
+  void Wait();
+
+ private:
+  // FrameTreeNode::Observer
+  std::unique_ptr<FrameTreeNodeObserverImpl> impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameFocusedObserver);
+};
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_BROWSER_TEST_UTILS_H_