Release mouse pointer capture when it starts drag

third_party/WebKit/Source/platform/WebPointerEvent.cpp

Index: third_party/WebKit/Source/platform/WebPointerEvent.cpp
diff --git a/third_party/WebKit/Source/platform/WebPointerEvent.cpp b/third_party/WebKit/Source/platform/WebPointerEvent.cpp
index 21158c0b3658d464729ebae0b2b26a3cb693995b..f63d23210c1512ac31a7b3e7aef9b037015c4887 100644
--- a/third_party/WebKit/Source/platform/WebPointerEvent.cpp
+++ b/third_party/WebKit/Source/platform/WebPointerEvent.cpp
@@ -10,6 +10,23 @@ namespace blink {
 
 namespace {
 
+WebInputEvent::Type PointerEventTypeForMouseEventType(WebInputEvent::Type type,
+                                                      bool is_cancel) {
+  if (is_cancel)
+    return WebInputEvent::Type::kPointerCancel;
+  switch (type) {
+    case WebInputEvent::Type::kMouseDown:
+      return WebInputEvent::Type::kPointerDown;
+    case WebInputEvent::Type::kMouseUp:
+      return WebInputEvent::Type::kPointerUp;
+    case WebInputEvent::Type::kMouseMove:
+      return WebInputEvent::Type::kPointerMove;
+    default:
+      NOTREACHED();
+      return WebInputEvent::Type::kUndefined;
+  }
+}
+
 WebInputEvent::Type PointerEventTypeForTouchPointState(
     WebTouchPoint::State state) {
   switch (state) {
@@ -27,6 +44,7 @@ WebInputEvent::Type PointerEventTypeForTouchPointState(
       return WebInputEvent::Type::kUndefined;
   }
 }
+
 }  // namespace
 
 WebPointerEvent::WebPointerEvent(const WebTouchEvent& touch_event,
@@ -50,6 +68,19 @@ WebPointerEvent::WebPointerEvent(const WebTouchEvent& touch_event,
   rotation_angle = touch_point.rotation_angle;
 }
 
+WebPointerEvent::WebPointerEvent(const WebMouseEvent& mouse_event,
+                                 bool is_cancel)
+    : WebInputEvent(sizeof(WebPointerEvent)),
+      WebPointerProperties(mouse_event),
+      width(1),
+      height(1) {
+  SetFrameScale(mouse_event.FrameScale());
+  SetFrameTranslate(mouse_event.FrameTranslate());
+  SetTimeStampSeconds(mouse_event.TimeStampSeconds());
+  SetType(PointerEventTypeForMouseEventType(mouse_event.GetType(), is_cancel));
+  SetModifiers(mouse_event.GetModifiers());
+}
+
 WebPointerEvent WebPointerEvent::WebPointerEventInRootFrame() const {
   WebPointerEvent transformed_event = *this;
   transformed_event.width /= frame_scale_;