Provide WebVR pose data only to the focused frame.

third_party/WebKit/Source/core/page/FocusChangedObserver.cpp

Index: third_party/WebKit/Source/core/page/FocusChangedObserver.cpp
diff --git a/third_party/WebKit/Source/core/page/FocusChangedObserver.cpp b/third_party/WebKit/Source/core/page/FocusChangedObserver.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..9e4b0dba135c301afab973ff46239606b2f444d6
--- /dev/null
+++ b/third_party/WebKit/Source/core/page/FocusChangedObserver.cpp
@@ -0,0 +1,27 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/page/FocusChangedObserver.h"
+
+#include "core/page/FocusController.h"
+#include "core/page/Page.h"
+
+namespace blink {
+
+FocusChangedObserver::FocusChangedObserver(Page* page) {
+  DCHECK(page);
+  page->focusController().registerFocusChangedObserver(this);
+}
+
+bool FocusChangedObserver::isFrameFocused(LocalFrame* frame) {
+  if (!frame)
+    return false;
+  Page* page = frame->page();
+  if (!page)
+    return false;
+  const FocusController& controller = page->focusController();
+  return controller.isFocused() && (controller.focusedFrame() == frame);
+}
+
+}  // namespace blink