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..361c798d47b6cd79f51b0aff23e24a45bbc24531 100644
--- a/third_party/WebKit/Source/core/page/FocusController.cpp
+++ b/third_party/WebKit/Source/core/page/FocusController.cpp
@@ -55,6 +55,7 @@
 #include "core/html/TextControlElement.h"
 #include "core/input/EventHandler.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"
@@ -766,6 +767,8 @@ 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 +871,8 @@ void FocusController::setFocused(bool focused) {
     dispatchEventsOnWindowAndFocusedElement(
         toLocalFrame(m_focusedFrame.get())->document(), focused);
   }
+
+  notifyFocusChangedObservers();

[jbroman, 2017/02/02 16:07:20]

Won't this possibly notify twice, since setFocusedFrame also does so?

[mthiesse, 2017/02/02 17:52:18]

Yes, intentionally. We need to call it in setFocusedFrame, because that's called
from a bunch of places, but setFocused also changes whether or not the "Focused
Frame" is actually focused, even if it doesn't change the "Focused Frame". I
didn't want to check from setFocused whether or not setFocusedFrame would be
called, whether it would return early, etc. to avoid notifying twice.

I could separate this into two callbacks, observer->focusedFrameChanged and
observer->focusChanged if that helps?

 }
 
 bool FocusController::setInitialFocus(WebFocusType type) {
@@ -1396,9 +1401,23 @@ 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 (auto& it : m_focusChangedObservers) {

[jbroman, 2017/02/02 16:07:20]

nit: const auto&

[mthiesse, 2017/02/02 17:52:18]

Done.

+    it->focusedFrameChanged();
+  }

[jbroman, 2017/02/02 16:07:20]

super-nit: don't need the braces

[mthiesse, 2017/02/02 17:52:18]

Done.

+}
+
 DEFINE_TRACE(FocusController) {
   visitor->trace(m_page);
   visitor->trace(m_focusedFrame);
+  visitor->trace(m_focusChangedObservers);
 }
 
 }  // namespace blink