Release mouse pointer capture when it starts drag

third_party/WebKit/Source/core/events/PointerEventFactory.cpp

Index: third_party/WebKit/Source/core/events/PointerEventFactory.cpp
diff --git a/third_party/WebKit/Source/core/events/PointerEventFactory.cpp b/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
index 8fd5795fbc720994c6ac31421adbde80c6746a21..233c45501157f4b06027a8ddb26c9efc54d0f12e 100644
--- a/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
+++ b/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
@@ -368,6 +368,16 @@ PointerEvent* PointerEventFactory::Create(
                               event_platform_time_stamp);
 }
 
+PointerEvent* PointerEventFactory::CreatePointerCancelEvent(
+    const WebPointerEvent& event) {
+  DCHECK_EQ(event.GetType(), WebInputEvent::Type::kPointerCancel);
+  int pointer_id = GetPointerEventId(event);
+
+  return CreatePointerCancelEvent(
+      pointer_id, event.pointer_type,
+      TimeTicks::FromSeconds(event.TimeStampSeconds()));
+}
+
 PointerEvent* PointerEventFactory::CreatePointerCancelEvent(
     const int pointer_id,
     const WebPointerProperties::PointerType pointer_type,