Release mouse pointer capture when it starts drag

third_party/WebKit/Source/platform/WebPointerEvent.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "public/platform/WebPointerEvent.h"
 
 #include "public/platform/WebFloatPoint.h"
 
 namespace blink {
 
 namespace {
 
 WebInputEvent::Type PointerEventTypeForTouchPointState(
     WebTouchPoint::State state) {
   switch (state) {
     case WebTouchPoint::kStateReleased:
       return WebInputEvent::Type::kPointerUp;
     case WebTouchPoint::kStateCancelled:
       return WebInputEvent::Type::kPointerCancel;
     case WebTouchPoint::kStatePressed:
       return WebInputEvent::Type::kPointerDown;
     case WebTouchPoint::kStateMoved:
       return WebInputEvent::Type::kPointerMove;
     case WebTouchPoint::kStateStationary:
     default:
       NOTREACHED();
       return WebInputEvent::Type::kUndefined;
   }
 }
+
 }  // namespace
 
 WebPointerEvent::WebPointerEvent(const WebTouchEvent& touch_event,
                                  const WebTouchPoint& touch_point)
     : WebInputEvent(sizeof(WebPointerEvent)),
       WebPointerProperties(touch_point),
       // TODO(crbug.com/731725): This mapping needs a times by 2.
       width(touch_point.radius_x),
       height(touch_point.radius_y) {
   // WebInutEvent attributes
   SetFrameScale(touch_event.FrameScale());
   SetFrameTranslate(touch_event.FrameTranslate());
   SetTimeStampSeconds(touch_event.TimeStampSeconds());
   SetType(PointerEventTypeForTouchPointState(touch_point.state));
   SetModifiers(touch_event.GetModifiers());
   // WebTouchEvent attributes
   dispatch_type = touch_event.dispatch_type;
   moved_beyond_slop_region = touch_event.moved_beyond_slop_region;
   touch_start_or_first_touch_move = touch_event.touch_start_or_first_touch_move;
   // WebTouchPoint attributes
   rotation_angle = touch_point.rotation_angle;
 }
 
+WebPointerEvent::WebPointerEvent(WebInputEvent::Type type,
+                                 const WebMouseEvent& mouse_event)
+    : WebInputEvent(sizeof(WebPointerEvent)),
+      WebPointerProperties(mouse_event),
+      width(1),
+      height(1) {
+  DCHECK_GE(type, WebInputEvent::kPointerTypeFirst);
+  DCHECK_LE(type, WebInputEvent::kPointerTypeLast);
+  SetFrameScale(mouse_event.FrameScale());
+  SetFrameTranslate(mouse_event.FrameTranslate());
+  SetTimeStampSeconds(mouse_event.TimeStampSeconds());
+  SetType(type);
+  SetModifiers(mouse_event.GetModifiers());
+}
+
 WebPointerEvent WebPointerEvent::WebPointerEventInRootFrame() const {
   WebPointerEvent transformed_event = *this;
   transformed_event.width /= frame_scale_;
   transformed_event.height /= frame_scale_;
   transformed_event.movement_x /= frame_scale_;
   transformed_event.movement_y /= frame_scale_;
   transformed_event.position_in_widget_ =
       WebFloatPoint((transformed_event.PositionInWidget().x / frame_scale_) +
                         frame_translate_.x,
                     (transformed_event.PositionInWidget().y / frame_scale_) +
                         frame_translate_.y);
   return transformed_event;
 }
 
 }  // namespace blink