Remove the (already disabled) OverflowChangedEvent runtime flag

Source/core/layout/LayoutBlock.cpp

Index: Source/core/layout/LayoutBlock.cpp
diff --git a/Source/core/layout/LayoutBlock.cpp b/Source/core/layout/LayoutBlock.cpp
index 431f7599831f5c52c161c32cf917fb835a981be1..1c42b8f5f32f447357b160846bd0be3be5e05680 100644
--- a/Source/core/layout/LayoutBlock.cpp
+++ b/Source/core/layout/LayoutBlock.cpp
@@ -33,7 +33,6 @@
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/htmlediting.h"
-#include "core/events/OverflowEvent.h"
 #include "core/fetch/ResourceLoadPriorityOptimizer.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ -98,49 +97,6 @@ typedef WTF::HashSet<LayoutBlock*> DelayedUpdateScrollInfoSet;
 static int gDelayUpdateScrollInfo = 0;
 static DelayedUpdateScrollInfoSet* gDelayedUpdateScrollInfoSet = nullptr;
 
-// This class helps dispatching the 'overflow' event on layout change. overflow can be set on LayoutBoxes, yet the existing code
-// only works on LayoutBlocks. If this changes, this class should be shared with other LayoutBoxes.
-class OverflowEventDispatcher {
-    WTF_MAKE_NONCOPYABLE(OverflowEventDispatcher);
-public:
-    OverflowEventDispatcher(const LayoutBlock* block)
-        : m_block(block)
-        , m_hadHorizontalLayoutOverflow(false)
-        , m_hadVerticalLayoutOverflow(false)
-    {
-        m_shouldDispatchEvent = !m_block->isAnonymous() && m_block->hasOverflowClip() && m_block->document().hasListenerType(Document::OVERFLOWCHANGED_LISTENER);
-        if (m_shouldDispatchEvent) {
-            m_hadHorizontalLayoutOverflow = m_block->hasHorizontalLayoutOverflow();
-            m_hadVerticalLayoutOverflow = m_block->hasVerticalLayoutOverflow();
-        }
-    }
-
-    ~OverflowEventDispatcher()
-    {
-        if (!m_shouldDispatchEvent)
-            return;
-
-        bool hasHorizontalLayoutOverflow = m_block->hasHorizontalLayoutOverflow();
-        bool hasVerticalLayoutOverflow = m_block->hasVerticalLayoutOverflow();
-
-        bool horizontalLayoutOverflowChanged = hasHorizontalLayoutOverflow != m_hadHorizontalLayoutOverflow;
-        bool verticalLayoutOverflowChanged = hasVerticalLayoutOverflow != m_hadVerticalLayoutOverflow;
-
-        if (!horizontalLayoutOverflowChanged && !verticalLayoutOverflowChanged)
-            return;
-
-        RefPtrWillBeRawPtr<OverflowEvent> event = OverflowEvent::create(horizontalLayoutOverflowChanged, hasHorizontalLayoutOverflow, verticalLayoutOverflowChanged, hasVerticalLayoutOverflow);
-        event->setTarget(m_block->node());
-        m_block->document().enqueueAnimationFrameEvent(event.release());
-    }
-
-private:
-    const LayoutBlock* m_block;
-    bool m_shouldDispatchEvent;
-    bool m_hadHorizontalLayoutOverflow;
-    bool m_hadVerticalLayoutOverflow;
-};
-
 LayoutBlock::LayoutBlock(ContainerNode* node)
     : LayoutBox(node)
     , m_hasMarginBeforeQuirk(false)
@@ -896,7 +852,6 @@ void LayoutBlock::updateScrollInfoAfterLayout()
 void LayoutBlock::layout()
 {
     LayoutAnalyzer::Scope analyzer(*this);
-    OverflowEventDispatcher dispatcher(this);
 
     // Table cells call layoutBlock directly, so don't add any logic here.  Put code into
     // layoutBlock().