ResizeObserver pt4: IDL methods

Implements ResizeObserver and ResizeObserverEntry IDL calls.

observe/unobserver connect ResizeObserver and Element through ElementRareData.
ElementRareData has a map (ResizeObserver->ResizeObservation)

Design doc at: https://docs.google.com/document/d/1G4OmqqlFY3H3erQAUmteKES02-bIECikDjWBrDKH9PA/edit?usp=sharing
BUG=612962

Review-Url: https://codereview.chromium.org/2185533004
Cr-Commit-Position: refs/heads/master@{#407973}

third_party/WebKit/Source/core/observer/ResizeObserver.cpp

@@ -5,9 +5,11 @@
 #include "core/observer/ResizeObserver.h"
 
 #include "core/dom/Element.h"
+#include "core/frame/FrameView.h"
 #include "core/observer/ResizeObservation.h"
 #include "core/observer/ResizeObserverCallback.h"
 #include "core/observer/ResizeObserverController.h"
+#include "core/observer/ResizeObserverEntry.h"
 
 namespace blink {
 
@@ -25,14 +27,40 @@ ResizeObserver::ResizeObserver(ResizeObserverCallback* callback, Document& docum
 
 void ResizeObserver::observe(Element* target)
 {
+    auto& observerMap = target->ensureResizeObserverData();
+    if (observerMap.contains(this))
+        return; // Already registered.
+
+    auto observation = new ResizeObservation(target, this);
+    m_observations.add(observation);
+    observerMap.set(this, observation);
+
+    if (FrameView* frameView = target->document().view())
+        frameView->scheduleAnimation();
 }
 
 void ResizeObserver::unobserve(Element* target)
 {
+    auto observerMap = target ? target->resizeObserverData() : nullptr;
+    if (!observerMap)
+        return;
+    auto observation = observerMap->find(this);
+    if (observation != observerMap->end()) {
+        m_observations.remove((*observation).value);
+        observerMap->remove(observation);
+    }
 }
 
 void ResizeObserver::disconnect()
 {
+    ObservationList observations;
+    m_observations.swap(observations);
+
+    for (auto observation : observations) {
+        Element* target = (*observation).target();
+        if (target)
+            target->ensureResizeObserverData().remove(this);
+    }
 }
 
 DEFINE_TRACE(ResizeObserver)

third_party/WebKit/Source/core/observer/ResizeObserverEntry.cpp

@@ -5,7 +5,6 @@
 #include "core/observer/ResizeObserverEntry.h"
 
 #include "core/dom/ClientRect.h"
-#include "core/dom/DOMRectReadOnly.h"
 #include "core/dom/Element.h"
 #include "core/layout/LayoutBox.h"
 #include "core/observer/ResizeObservation.h"
@@ -17,6 +16,18 @@ class ResizeObservation;
 ResizeObserverEntry::ResizeObserverEntry(Element* target)
     : m_target(target)
 {
+    FloatSize size = FloatSize(ResizeObservation::getTargetSize(m_target));
+    FloatPoint location;
+    LayoutBox* layout = m_target ? m_target->layoutBox() : nullptr;
+    if (layout) {
+        location = FloatPoint(layout->paddingLeft(), layout->paddingTop());
+    }
+    m_contentRect = ClientRect::create(FloatRect(location, size));
+}
+
+LayoutSize ResizeObserverEntry::contentSize() const
+{
+    return LayoutSize(m_contentRect->width(), m_contentRect->height());
 }
 
 DEFINE_TRACE(ResizeObserverEntry)

third_party/WebKit/Source/core/observer/ResizeObserverEntry.h

@@ -11,7 +11,6 @@
 namespace blink {
 
 class Element;
-class DOMRectReadOnly;
 class ClientRect;
 class LayoutSize;
 
@@ -24,6 +23,7 @@ class ResizeObserverEntry final : public GarbageCollected<ResizeObserverEntry>,
     Element* target() const { return m_target; }
     // FIXME(atotic): should return DOMRectReadOnly once https://crbug.com/388780 lands
     ClientRect* contentRect() const { return m_contentRect; }
+    LayoutSize contentSize() const;
 
     DECLARE_VIRTUAL_TRACE();