Implement screen orientation for out-of-process iframes.

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

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 7fdceb563e02fc978e8b27d8013257a931985c6e..902af0ea546eccf37ed8a945f018c81f9b3855cc 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -529,21 +529,24 @@ void LocalDOMWindow::Reset() {
 
 void LocalDOMWindow::SendOrientationChangeEvent() {
   ASSERT(RuntimeEnabledFeatures::orientationEventEnabled());
-  ASSERT(GetFrame()->IsMainFrame());
+  DCHECK(GetFrame()->IsLocalRoot());
 
   // Before dispatching the event, build a list of all frames in the page
   // to send the event to, to mitigate side effects from event handlers
   // potentially interfering with others.
-  HeapVector<Member<Frame>> frames;
-  for (Frame* f = GetFrame(); f; f = f->Tree().TraverseNext())
-    frames.push_back(f);
-
-  for (size_t i = 0; i < frames.size(); ++i) {
-    if (!frames[i]->IsLocalFrame())
-      continue;
-    ToLocalFrame(frames[i].Get())
-        ->DomWindow()
-        ->DispatchEvent(Event::Create(EventTypeNames::orientationchange));
+  HeapVector<Member<LocalFrame>> frames;
+  frames.push_back(GetFrame());
+  for (size_t i = 0; i < frames.size(); i++) {
+    for (Frame* child = frames[i]->Tree().FirstChild(); child;
+         child = child->Tree().NextSibling()) {
+      if (child->IsLocalFrame())
+        frames.push_back(ToLocalFrame(child));
+    }
+  }

[haraken, 2017/04/25 12:35:39]

What is this change for? Does TraverseNext not traverse all child frames?

[lfg, 2017/04/25 15:44:31]

The problem with TraverseNext is that it traverses all child frames (including
remote frames), but we only want to traverse the local frames within the current
local root.

For example, if we have A->B->A (a.com with a subframe in b.com with a subframe
in a.com), then using TraverseNext would traverse the local frames within the
subframe in A. But we don't want to do that, as the WebFrameWidget in A's
subframe will also get the event.

+
+  for (LocalFrame* frame : frames) {
+    frame->DomWindow()->DispatchEvent(

[haraken, 2017/04/25 16:21:02]

Nit: We should have renamed DomWindow to DOMWindow :)

+        Event::Create(EventTypeNames::orientationchange));

[mlamouri (slow - plz ping), 2017/04/25 11:06:47]

Note that screen orientation has two parts. One of them lives in
ScreenOrientationControllerImpl::NotifyOrientationChanged(). It seems that it
should work too but I prefer to make sure you are aware of this :)

[haraken, 2017/04/25 12:35:39]

Yeah , I'd also prefer not adding feature-specific code to LocalDOMWindow :)

[lfg, 2017/04/25 15:44:31]

Yes, this change is basically aligning LocalDOMWindow with
ScreenOrientationControllerImpl. The implementation in
ScreenOrientationControllerImpl is recursive, so it's slightly different, but it
essentially does the same thing (skips the RemoteFrames and its children). See
the comment above to haraken@'s question for a detailed explanation.

[haraken, 2017/04/25 16:21:02]

Can we clean up the code a bit more so that we don't need to have slightly
different logics in two different files? A follow-up CL is fine.

   }
 }