Make Fullscreen::requestFullscreen and exitFullscreen static

third_party/WebKit/Source/modules/vr/VRDisplay.cpp

Index: third_party/WebKit/Source/modules/vr/VRDisplay.cpp
diff --git a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
index 8ad6ddf665e090a0d4c501baf0322865d6d83a12..ad76fa1bde27e0eb040af2ef5d7de36536dabb3c 100644
--- a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
+++ b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
@@ -170,7 +170,7 @@ ScriptPromise VRDisplay::requestPresent(ScriptState* scriptState, const HeapVect
             // TODO: Need a proper VR compositor, but for the moment on mobile
             // we'll just make the canvas fullscreen so that VrShell can pick it
             // up through the standard (high latency) compositing path.
-            Fullscreen::from(m_layer.source()->document()).requestFullscreen(*m_layer.source(), Fullscreen::UnprefixedRequest);
+            Fullscreen::requestFullscreen(*m_layer.source(), Fullscreen::UnprefixedRequest);
 
             m_isPresenting = true;