Rename PageLifecycleObserver to PageVisibilityObserver

third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp

Index: third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp
diff --git a/third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp b/third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp
index 3062214e7229e9ab33b0ab4fb792689a68c3b313..6b1f3db0eb41fecfa6d66d04098d2955c5220465 100644
--- a/third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp
+++ b/third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp
@@ -63,13 +63,13 @@ void ScreenWakeLock::contextDestroyed()
 DEFINE_TRACE(ScreenWakeLock)
 {
     Supplement<LocalFrame>::trace(visitor);
-    PageLifecycleObserver::trace(visitor);
+    PageVisibilityObserver::trace(visitor);
     ContextLifecycleObserver::trace(visitor);
 }
 
 ScreenWakeLock::ScreenWakeLock(LocalFrame& frame)
     : ContextLifecycleObserver(frame.document())
-    , PageLifecycleObserver(frame.page())
+    , PageVisibilityObserver(frame.page())
     , m_keepAwake(false)
 {
     DCHECK(!m_service.is_bound());