Fix RLS OOPIF lifecycle DCHECK in ScrollingCoordinator.

ScrollingCoordinator::FrameScrollerIsDirty reads the main frame's
compositing state, so it isn't safe to call it after the compositing
update of a non-main local root.

TESTED=SitePerProcessTextInputManagerTest passes with RLS

Bug: 802274
Change-Id: I04418c26d9ab33c60c99765434db5493138aaa3f
Reviewed-on: https://chromium-review.googlesource.com/881581Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#531394}

third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp

@@ -171,12 +171,6 @@ void ScrollingCoordinator::UpdateAfterCompositingChangeIfNeeded(
   LocalFrame* frame = &frame_view->GetFrame();
   DCHECK(frame->IsLocalRoot());
 
-  if (!(frame_view->ScrollGestureRegionIsDirty() ||
-        touch_event_target_rects_are_dirty_ ||
-        should_scroll_on_main_thread_dirty_ || FrameScrollerIsDirty())) {
-    return;
-  }
-
   TRACE_EVENT0("input",
                "ScrollingCoordinator::updateAfterCompositingChangeIfNeeded");
 
@@ -202,6 +196,11 @@ void ScrollingCoordinator::UpdateAfterCompositingChangeIfNeeded(
   if (frame != frame_view->GetPage()->MainFrame())
     return;
 
+  if (!(touch_event_target_rects_are_dirty_ ||
+        should_scroll_on_main_thread_dirty_ || FrameScrollerIsDirty())) {
+    return;
+  }
+
   if (touch_event_target_rects_are_dirty_) {
     UpdateTouchEventTargetRectsIfNeeded();
     touch_event_target_rects_are_dirty_ = false;