Send lostpointercapture on touch capturing

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 6523dac47b4d641b4552b341d50e41fc7b81a1bc..1c5afa56ac770a822255f033548c83cd4e5bbaba 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -2651,6 +2651,10 @@ void Element::setPointerCapture(int pointerId, ExceptionState& exceptionState)
             exceptionState.throwDOMException(InvalidPointerId, "InvalidPointerId");
         else if (!inDocument())
             exceptionState.throwDOMException(InvalidStateError, "InvalidStateError");
+        // TODO(crbug.com/579553): This next "else if" is a hack to notify JS that we don't (yet) support
+        // explicit set/release of touch pointers (which are implicitly captured for performance reasons).
+        else if (document().frame()->eventHandler().getPointerEventType(pointerId) == WebPointerProperties::PointerType::Touch)
+            exceptionState.throwDOMException(InvalidPointerId, "InvalidPointerId");
         else
             document().frame()->eventHandler().setPointerCapture(pointerId, this);
     }
@@ -2661,6 +2665,10 @@ void Element::releasePointerCapture(int pointerId, ExceptionState& exceptionStat
     if (document().frame()) {
         if (!document().frame()->eventHandler().isPointerEventActive(pointerId))
             exceptionState.throwDOMException(InvalidPointerId, "InvalidPointerId");
+        // TODO(crbug.com/579553): This next "else if" is a hack to notify JS that we don't (yet) support
+        // explicit set/release of touch pointers (which are implicitly captured for performance reasons).
+        else if (document().frame()->eventHandler().getPointerEventType(pointerId) == WebPointerProperties::PointerType::Touch)
+            exceptionState.throwDOMException(InvalidPointerId, "InvalidPointerId");
         else
             document().frame()->eventHandler().releasePointerCapture(pointerId, this);
     }