Initial ResizeObserver implementation

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 fa8b38802cb6b0846b7f5ea4280e7666a3efba79..33256b34f42345a69c458b3163eee423aae1cd11 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -38,6 +38,7 @@
 #include "core/editing/FrameSelection.h"
 #include "core/editing/RenderedPosition.h"
 #include "core/editing/markers/DocumentMarkerController.h"
+#include "core/events/ErrorEvent.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameHost.h"
@@ -73,6 +74,7 @@
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
+#include "core/observer/ResizeObserverController.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/FocusController.h"
@@ -2505,6 +2507,38 @@ void FrameView::scheduleVisualUpdateForPaintInvalidationIfNeeded()
     // Otherwise the paint invalidation will be handled in paint invalidation phase of this cycle.
 }
 
+void FrameView::notifyResizeObserver()
+{
+    if (!m_frame->document()->resizeObserverController())

[eae, 2016/07/13 23:39:47]

When would notifyResizeObserver ever be called if the document doesn't have a
resizeObserverController? A comment explaining the edge case would be helpful!

[atotic1, 2016/07/15 01:43:17]

Controller is allocated only if ResizeObserver is created. This is a common
case.

+        return;
+
+    ResizeObserverController& resizeController = m_frame->document()->ensureResizeObserverController();
+
+    DCHECK(lifecycle().state() >= DocumentLifecycle::LayoutClean);
+
+    size_t resizeNotifyCount = 0;
+
+    while (resizeController.gatherObservations()) {
+        if (++resizeNotifyCount > ResizeObserverController::kRenderLoopLimit) {
+            resizeController.clearObservations();
+            // Report the error.

[eae, 2016/07/13 23:39:47]

Please remove redundant comment.

[atotic1, 2016/07/15 01:43:17]

Done.

+            ErrorEvent * error = ErrorEvent::create("ResizeObserver loop limit exceeded", SourceLocation::capture(m_frame->document()), nullptr);
+            m_frame->document()->reportException(error, NotSharableCrossOrigin);
+            // Ensure notifications will get delivered in next cycle.
+            if (FrameView* frameView = m_frame->view())
+                frameView->scheduleAnimation();
+            break;
+        }
+
+        resizeController.deliverObservations();
+
+        if (lifecycle().state() < DocumentLifecycle::LayoutClean || layoutView()->needsLayout())
+            updateStyleAndLayoutIfNeededRecursive();
+    }
+
+    DCHECK(!layoutView()->needsLayout());
+}
+
 // TODO(leviw): We don't assert lifecycle information from documents in child PluginViews.
 void FrameView::updateLifecyclePhasesInternal(DocumentLifecycle::LifecycleState targetState)
 {
@@ -2533,6 +2567,8 @@ void FrameView::updateLifecyclePhasesInternal(DocumentLifecycle::LifecycleState
         return;
     }
 
+    notifyResizeObserver();
+
     if (LayoutViewItem view = layoutViewItem()) {
         forAllNonThrottledFrameViews([](FrameView& frameView) {
             frameView.checkDoesNotNeedLayout();