IntersectionObserver: second cut.

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 29096603d9b63a9755fa09492108724c80373533..6cb14a4180770bb1d114beabd115b2d566d876b5 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -33,6 +33,7 @@
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/Fullscreen.h"
+#include "core/dom/IntersectionObservationRegistry.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/RenderedPosition.h"
@@ -121,7 +122,7 @@ FrameView::FrameView(LocalFrame* frame)
     , m_inSynchronousPostLayout(false)
     , m_postLayoutTasksTimer(this, &FrameView::postLayoutTimerFired)
     , m_updateWidgetsTimer(this, &FrameView::updateWidgetsTimerFired)
-    , m_intersectionObserverNotificationFactory(CancellableTaskFactory::create(this, &FrameView::notifyIntersectionObservers))
+    , m_renderThrottlingObserverNotificationFactory(CancellableTaskFactory::create(this, &FrameView::notifyRenderThrottlingObservers))
     , m_isTransparent(false)
     , m_baseBackgroundColor(Color::white)
     , m_mediaType(MediaTypeNames::screen)
@@ -285,7 +286,7 @@ void FrameView::dispose()
 
     if (m_didScrollTimer.isActive())
         m_didScrollTimer.stop();
-    m_intersectionObserverNotificationFactory->cancel();
+    m_renderThrottlingObserverNotificationFactory->cancel();
 
     // FIXME: Do we need to do something here for OOPI?
     HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
@@ -2395,10 +2396,8 @@ void FrameView::updateLifecyclePhasesInternal(LifeCycleUpdateOption phases)
     updateStyleAndLayoutIfNeededRecursive();
     ASSERT(lifecycle().state() >= DocumentLifecycle::LayoutClean);
 
-    if (phases == OnlyUpToLayoutClean) {
-        updateViewportIntersectionsForSubtree();
+    if (phases == OnlyUpToLayoutClean)
         return;
-    }
 
     if (LayoutView* view = layoutView()) {
         TRACE_EVENT1("devtools.timeline", "UpdateLayerTree", "data", InspectorUpdateLayerTreeEvent::data(m_frame.get()));
@@ -3949,36 +3948,34 @@ void FrameView::setNeedsUpdateViewportIntersection()
 
 void FrameView::updateViewportIntersectionIfNeeded()
 {
-    // TODO(skyostil): Replace this with a real intersection observer.
-    if (!m_needsUpdateViewportIntersection)
-        return;
-    m_needsUpdateViewportIntersection = false;
-    m_viewportIntersectionValid = true;
+    if (m_needsUpdateViewportIntersection) {
+        FrameView* parent = parentFrameView();
+        if (parent) {
+            ASSERT(!parent->m_needsUpdateViewportIntersection);
 
-    FrameView* parent = parentFrameView();
-    if (!parent) {
-        m_viewportIntersection = frameRect();
-        return;
-    }
-    ASSERT(!parent->m_needsUpdateViewportIntersection);
-
-    // If our parent is hidden, then we are too.
-    if (parent->m_viewportIntersection.isEmpty()) {
-        m_viewportIntersection = parent->m_viewportIntersection;
-        return;
+            // If our parent is hidden, then we are too.
+            if (parent->m_viewportIntersection.isEmpty()) {
+                m_viewportIntersection = parent->m_viewportIntersection;
+            } else {
+                // Transform our bounds into the root frame's content coordinate space,
+                // making sure we have valid layout data in our parent document. If our
+                // parent is throttled, we'll use possible stale layout information and
+                // rely on the fact that another lifecycle update will be scheduled once
+                // our parent becomes unthrottled.
+                ASSERT(parent->lifecycle().state() >= DocumentLifecycle::LayoutClean || parent->shouldThrottleRendering());
+                m_viewportIntersection = parent->contentsToRootFrame(frameRect());
+
+                // TODO(skyostil): Expand the viewport to make it less likely to see stale content while scrolling.
+                IntRect viewport = parent->m_viewportIntersection;
+                m_viewportIntersection.intersect(viewport);
+            }
+        } else {
+            m_viewportIntersection = frameRect();
+        }
     }
 
-    // Transform our bounds into the root frame's content coordinate space,
-    // making sure we have valid layout data in our parent document. If our
-    // parent is throttled, we'll use possible stale layout information and
-    // rely on the fact that another lifecycle update will be scheduled once
-    // our parent becomes unthrottled.
-    ASSERT(parent->lifecycle().state() >= DocumentLifecycle::LayoutClean || parent->shouldThrottleRendering());
-    m_viewportIntersection = parent->contentsToRootFrame(frameRect());
-
-    // TODO(skyostil): Expand the viewport to make it less likely to see stale content while scrolling.
-    IntRect viewport = parent->m_viewportIntersection;
-    m_viewportIntersection.intersect(viewport);
+    m_needsUpdateViewportIntersection = false;
+    m_viewportIntersectionValid = true;
 }
 
 void FrameView::updateViewportIntersectionsForSubtree()
@@ -3986,9 +3983,14 @@ void FrameView::updateViewportIntersectionsForSubtree()
     bool hadValidIntersection = m_viewportIntersectionValid;
     bool hadEmptyIntersection = m_viewportIntersection.isEmpty();
     updateViewportIntersectionIfNeeded();
+
+    // Notify javascript IntersectionObservers
+    frame().document()->intersectionObservationRegistry()->computeIntersectionObservations();
+
+    // Adjust render throttling for iframes based on visibility
     bool shouldNotify = !hadValidIntersection || hadEmptyIntersection != m_viewportIntersection.isEmpty();
-    if (shouldNotify && !m_intersectionObserverNotificationFactory->isPending())
-        m_frame->frameScheduler()->timerTaskRunner()->postTask(BLINK_FROM_HERE, m_intersectionObserverNotificationFactory->cancelAndCreate());
+    if (shouldNotify && !m_renderThrottlingObserverNotificationFactory->isPending())
+        m_frame->frameScheduler()->timerTaskRunner()->postTask(BLINK_FROM_HERE, m_renderThrottlingObserverNotificationFactory->cancelAndCreate());
 
     if (!m_needsUpdateViewportIntersectionInSubtree)
         return;
@@ -4002,9 +4004,9 @@ void FrameView::updateViewportIntersectionsForSubtree()
     }
 }
 
-void FrameView::notifyIntersectionObservers()
+void FrameView::notifyRenderThrottlingObservers()
 {
-    TRACE_EVENT0("blink", "FrameView::notifyIntersectionObservers");
+    TRACE_EVENT0("blink", "FrameView::notifyRenderThrottlingObservers");
     ASSERT(!isInPerformLayout());
     ASSERT(!m_frame->document()->inStyleRecalc());
     bool wasThrottled = canThrottleRendering();