Intersection Observer support for OOPIF

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

Index: third_party/WebKit/Source/core/frame/RemoteFrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/RemoteFrameView.cpp b/third_party/WebKit/Source/core/frame/RemoteFrameView.cpp
index d73ac0a12b1be30a510ebefa50124bbe42f465bd..d02f1999c84e448dd7c68d1b878a15ef40747536 100644
--- a/third_party/WebKit/Source/core/frame/RemoteFrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/RemoteFrameView.cpp
@@ -4,9 +4,13 @@
 
 #include "core/frame/RemoteFrameView.h"
 
+#include "core/dom/IntersectionObserverEntry.h"
 #include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
 #include "core/frame/RemoteFrame.h"
+#include "core/frame/RemoteFrameClient.h"
 #include "core/html/HTMLFrameOwnerElement.h"
+#include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutPartItem.h"
 
 namespace blink {
@@ -21,6 +25,10 @@ RemoteFrameView::~RemoteFrameView() {}
 void RemoteFrameView::setParent(Widget* parent) {
   Widget::setParent(parent);
   frameRectsChanged();
+  if (parent && parent->isFrameView())
+    startIntersectionObserver();
+  else
+    stopIntersectionObserver();
 }
 
 RemoteFrameView* RemoteFrameView::create(RemoteFrame* remoteFrame) {
@@ -29,6 +37,43 @@ RemoteFrameView* RemoteFrameView::create(RemoteFrame* remoteFrame) {
   return view;
 }
 
+void RemoteFrameView::startIntersectionObserver() {
+  DCHECK(m_remoteFrame->owner()->isLocal());
+  if (!m_intersectionObserver) {
+    m_intersectionObserver = IntersectionObserver::create(

[szager1, 2016/11/16 22:11:22]

This won't work, because the observer will only fire when you cross the given
threshold.  So, if the remote frame goes from 10% visible to 20% visible -- or
if the intersection rect changes without changing the visible ratio -- no
callback will fire.

[kenrb, 2016/11/21 19:37:35]

Thanks, I didn't realize this. I've reworked it to be more similar to the
original approach.

+        Vector<Length>(), Vector<float>({std::numeric_limits<float>::min()}),
+        &m_remoteFrame->deprecatedLocalOwner()->document(),
+        WTF::bind(&RemoteFrameView::onViewportIntersectionChanged,
+                  wrapWeakPersistent(this)));
+    m_intersectionObserver->setInitialState(
+        IntersectionObserver::InitialState::kAuto);
+    // startIntersectionObserver() should only be called on a RemoteFrame with
+    // a local owner, otherwise it doesn't correspond to a frame root in the
+    // remote process and therefore doesn't need to send intersection rects.
+    m_intersectionObserver->observe(m_remoteFrame->deprecatedLocalOwner());
+  }
+}
+
+void RemoteFrameView::stopIntersectionObserver() {
+  if (m_intersectionObserver) {
+    m_intersectionObserver->disconnect();
+    m_intersectionObserver = nullptr;
+  }
+}
+
+void RemoteFrameView::onViewportIntersectionChanged(
+    const HeapVector<Member<IntersectionObserverEntry>>& entries) {
+  ClientRect* rect = entries.last()->intersectionRect();
+  IntRect viewportIntersection = roundedIntRect(
+      FloatRect(rect->left(), rect->top(), rect->width(), rect->height()));
+  viewportIntersection = convertFromContainingWidget(viewportIntersection);
+  if (viewportIntersection != m_lastViewportIntersection) {
+    m_remoteFrame->client()->updateRemoteViewportIntersection(
+        viewportIntersection);
+  }
+  m_lastViewportIntersection = viewportIntersection;
+}
+
 void RemoteFrameView::dispose() {
   HTMLFrameOwnerElement* ownerElement = m_remoteFrame->deprecatedLocalOwner();
   // ownerElement can be null during frame swaps, because the
@@ -68,7 +113,7 @@ void RemoteFrameView::frameRectsChanged() {
   if (parent() && parent()->isFrameView())
     newRect = parent()->convertToRootFrame(
         toFrameView(parent())->contentsToFrame(newRect));
-  m_remoteFrame->frameRectsChanged(newRect);
+  m_remoteFrame->client()->frameRectsChanged(newRect);
 }
 
 void RemoteFrameView::hide() {
@@ -76,7 +121,8 @@ void RemoteFrameView::hide() {
 
   Widget::hide();
 
-  m_remoteFrame->visibilityChanged(false);
+  if (m_remoteFrame->client())
+    m_remoteFrame->client()->visibilityChanged(false);
 }
 
 void RemoteFrameView::show() {
@@ -84,7 +130,8 @@ void RemoteFrameView::show() {
 
   Widget::show();
 
-  m_remoteFrame->visibilityChanged(true);
+  if (m_remoteFrame->client())
+    m_remoteFrame->client()->visibilityChanged(true);
 }
 
 void RemoteFrameView::setParentVisible(bool visible) {
@@ -95,11 +142,13 @@ void RemoteFrameView::setParentVisible(bool visible) {
   if (!isSelfVisible())
     return;
 
-  m_remoteFrame->visibilityChanged(isVisible());
+  if (m_remoteFrame->client())
+    m_remoteFrame->client()->visibilityChanged(isVisible());
 }
 
 DEFINE_TRACE(RemoteFrameView) {
   visitor->trace(m_remoteFrame);
+  visitor->trace(m_intersectionObserver);
   Widget::trace(visitor);
 }