Change PlatformEventController to take LocalFrame rather than Page.

third_party/WebKit/Source/core/frame/PlatformEventController.cpp

Index: third_party/WebKit/Source/core/frame/PlatformEventController.cpp
diff --git a/third_party/WebKit/Source/core/frame/PlatformEventController.cpp b/third_party/WebKit/Source/core/frame/PlatformEventController.cpp
index 032c8e9d38c93c3c68069f39d4a1f01d74a52957..bf523742e73ad2416036c76340f953bd85244941 100644
--- a/third_party/WebKit/Source/core/frame/PlatformEventController.cpp
+++ b/third_party/WebKit/Source/core/frame/PlatformEventController.cpp
@@ -8,8 +8,8 @@
 
 namespace blink {
 
-PlatformEventController::PlatformEventController(Page* page)
-    : PageVisibilityObserver(page),
+PlatformEventController::PlatformEventController(LocalFrame* frame)

[dcheng, 2017/01/20 07:18:17]

Nit: I think this can be passed as mutable ref. Blink convention is to pass by
mutable reference as a signal that something should never be null.

[joelhockey, 2017/02/01 07:17:29]

Daniel, I must confess I don't know a lot of C++.  When I've searched about
mutable references, I only see talk about the mutable keyword for variable
declarations.  I don't think that is what you are talking about.

So are you saying to change
PlatformEventController::PlatformEventController(LocalFrame* frame)
to
PlatformEventController::PlatformEventController(LocalFrame &frame)
or something else?

+    : PageVisibilityObserver(frame->page()),
       m_hasEventListener(false),
       m_isActive(false),
       m_timer(this, &PlatformEventController::oneShotCallback) {}