Provide WebVR pose data only to the focused frame.

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

Index: third_party/WebKit/Source/core/page/FocusController.cpp
diff --git a/third_party/WebKit/Source/core/page/FocusController.cpp b/third_party/WebKit/Source/core/page/FocusController.cpp
index 28897fcea19a17f418c11d41059ae6d187670d50..c75f524ac1ac4de629c2045c739a8667a6e8457c 100644
--- a/third_party/WebKit/Source/core/page/FocusController.cpp
+++ b/third_party/WebKit/Source/core/page/FocusController.cpp
@@ -54,11 +54,13 @@
 #include "core/html/HTMLSlotElement.h"
 #include "core/html/TextControlElement.h"
 #include "core/input/EventHandler.h"
+#include "core/layout/HitTestResult.h"
 #include "core/page/ChromeClient.h"
+#include "core/page/FocusChangedObserver.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
-#include "core/layout/HitTestResult.h"
 #include "core/page/SpatialNavigation.h"
+
 #include <limits>
 
 namespace blink {
@@ -766,6 +768,8 @@ void FocusController::setFocusedFrame(Frame* frame, bool notifyEmbedder) {
   // part of dispatching the focus event above. See https://crbug.com/570874.
   if (m_focusedFrame && m_focusedFrame->client() && notifyEmbedder)
     m_focusedFrame->client()->frameFocused();
+
+  notifyFocusChangedObservers();
 }
 
 void FocusController::focusDocumentView(Frame* frame, bool notifyEmbedder) {
@@ -868,6 +872,8 @@ void FocusController::setFocused(bool focused) {
     dispatchEventsOnWindowAndFocusedElement(
         toLocalFrame(m_focusedFrame.get())->document(), focused);
   }
+
+  notifyFocusChangedObservers();
 }
 
 bool FocusController::setInitialFocus(WebFocusType type) {
@@ -1396,9 +1402,22 @@ bool FocusController::advanceFocusDirectionally(WebFocusType type) {
   return consumed;
 }
 
+void FocusController::registerFocusChangedObserver(
+    FocusChangedObserver* observer) {
+  DCHECK(observer);
+  DCHECK(!m_focusChangedObservers.contains(observer));
+  m_focusChangedObservers.insert(observer);
+}
+
+void FocusController::notifyFocusChangedObservers() const {
+  for (const auto& it : m_focusChangedObservers)
+    it->focusedFrameChanged();
+}
+
 DEFINE_TRACE(FocusController) {
   visitor->trace(m_page);
   visitor->trace(m_focusedFrame);
+  visitor->trace(m_focusChangedObservers);
 }
 
 }  // namespace blink