Communicate whether passive event listeners exist to cc.

third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp

Index: third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
index 84744848cfe370946fd1b638d8113ee47e8be747..3ae5cce9ffc833090085a7affc06387863f5e0c3 100644
--- a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
+++ b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
@@ -70,6 +70,8 @@ using blink::WebRect;
 using blink::WebScrollbarLayer;
 using blink::WebVector;
 
+namespace blink {
+
 namespace {
 
 WebLayer* toWebLayer(blink::GraphicsLayer* layer)
@@ -77,9 +79,17 @@ WebLayer* toWebLayer(blink::GraphicsLayer* layer)
     return layer ? layer->platformLayer() : nullptr;
 }
 
-} // namespace
+WebEventListenerProperties webEventListenerProperties(EventHandlerRegistry::EventHandlerClass blockingClass, EventHandlerRegistry::EventHandlerClass passiveClass, Page* page)
+{
+    WebEventListenerProperties result = WebEventListenerProperties::Nothing;
+    if (page->frameHost().eventHandlerRegistry().hasEventHandlers(blockingClass))
+        result |= WebEventListenerProperties::Blocking;
+    if (page->frameHost().eventHandlerRegistry().hasEventHandlers(passiveClass))
+        result |= WebEventListenerProperties::Passive;
+    return result;
+}
 
-namespace blink {
+} // namespace
 
 PassOwnPtrWillBeRawPtr<ScrollingCoordinator> ScrollingCoordinator::create(Page* page)
 {
@@ -680,7 +690,19 @@ void ScrollingCoordinator::willDestroyLayer(PaintLayer* layer)
     m_layersWithTouchRects.remove(layer);
 }
 
-void ScrollingCoordinator::updateHaveWheelEventHandlers()
+void ScrollingCoordinator::updateTouchEventListenerProperties()
+{
+    ASSERT(isMainThread());
+    ASSERT(m_page);
+    if (!m_page->mainFrame()->isLocalFrame() || !m_page->deprecatedLocalMainFrame()->view())
+        return;
+
+    if (WebLayer* scrollLayer = toWebLayer(m_page->deprecatedLocalMainFrame()->view()->layerForScrolling())) {

[aelias_OOO_until_Jul13, 2016/01/26 19:16:33]

Hmm, on the Blink side we only ever set it on the root scrolling layer.  So the
per-layer tracking and hit-testing stuff this patch has is actually equivalent
to a single root layer enum.  I see that was also the case with the wheel event
properties already.

When the slimming paint v2 change Rick mentioned happens, this code will be
fully deleted and replaced, so this layer-based tracking won't to ever be used
in a meaningful way.  So I'd indeed prefer this to be simplified down to a
global now.  Also, please replace the existing layer wheel event listener stuff
with a global.

[dtapuska, 2016/01/29 21:46:41]

Done.

+        scrollLayer->setTouchEventListenerProperties(webEventListenerProperties(EventHandlerRegistry::TouchEvent, EventHandlerRegistry::TouchEventPassive, m_page));
+    }
+}
+
+void ScrollingCoordinator::updateWheelEventListenerProperties()
 {
     ASSERT(isMainThread());
     ASSERT(m_page);
@@ -688,8 +710,7 @@ void ScrollingCoordinator::updateHaveWheelEventHandlers()
         return;
 
     if (WebLayer* scrollLayer = toWebLayer(m_page->deprecatedLocalMainFrame()->view()->layerForScrolling())) {
-        bool haveHandlers = m_page->frameHost().eventHandlerRegistry().hasEventHandlers(EventHandlerRegistry::WheelEvent);
-        scrollLayer->setHaveWheelEventHandlers(haveHandlers);
+        scrollLayer->setWheelEventListenerProperties(webEventListenerProperties(EventHandlerRegistry::WheelEvent, EventHandlerRegistry::WheelEventPassive, m_page));
     }
 }
 
@@ -960,7 +981,8 @@ void ScrollingCoordinator::frameViewRootLayerDidChange(FrameView* frameView)
         return;
 
     notifyGeometryChanged();
-    updateHaveWheelEventHandlers();
+    updateTouchEventListenerProperties();
+    updateWheelEventListenerProperties();
     updateHaveScrollEventHandlers();
 }