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 0bf16be20617d7cfa0226a03de91a2f3ede496c7..8cc4e93717f4dfaa6d28421dedb3551a7b9ac71b 100644
--- a/content/public/test/browser_test_utils.h
+++ b/content/public/test/browser_test_utils.h
@@ -520,6 +520,24 @@ class InputMsgWatcher : public BrowserMessageFilter {
   DISALLOW_COPY_AND_ASSIGN(InputMsgWatcher);
 };
 
+// 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.
+  struct 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_