Allow OOPIFs to capture mouse input while mouse button is held down

content/browser/renderer_host/render_widget_host_input_event_router.cc

 // Copyright 2015 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 "content/browser/renderer_host/render_widget_host_input_event_router.h"
 
 #include <vector>
 
 #include "base/metrics/histogram_macros.h"
 
@@ skipping 45 matching lines @@
   }
 
   // If the target that's being destroyed is in the gesture target queue, we
   // replace it with nullptr so that we maintain the 1:1 correspondence between
   // queue entries and the touch sequences that underly them.
   for (size_t i = 0; i < touchscreen_gesture_target_queue_.size(); ++i) {
     if (touchscreen_gesture_target_queue_[i].target == view)
       touchscreen_gesture_target_queue_[i].target = nullptr;
   }
 
+  if (view == mouse_capture_target_.target)
+    mouse_capture_target_.target = nullptr;
+
   if (view == touchscreen_gesture_target_.target)
     touchscreen_gesture_target_.target = nullptr;
 
   if (view == touchpad_gesture_target_.target)
     touchpad_gesture_target_.target = nullptr;
 
   if (view == bubbling_gesture_scroll_target_.target ||
       view == first_bubbling_scroll_target_.target) {
     bubbling_gesture_scroll_target_.target = nullptr;
     first_bubbling_scroll_target_.target = nullptr;
@@ skipping 85 matching lines @@
   // parent frame has not sent a new compositor frame since that happened.
   if (iter == owner_map_.end())
     return root_view;
 
   return iter->second;
 }
 
 void RenderWidgetHostInputEventRouter::RouteMouseEvent(
     RenderWidgetHostViewBase* root_view,
     blink::WebMouseEvent* event) {
+  RenderWidgetHostViewBase* target;
   gfx::Point transformed_point;
-  RenderWidgetHostViewBase* target = FindEventTarget(
-      root_view, gfx::Point(event->x, event->y), &transformed_point);
+  const int mouse_button_modifiers = blink::WebInputEvent::LeftButtonDown |
+                                     blink::WebInputEvent::MiddleButtonDown |
+                                     blink::WebInputEvent::RightButtonDown;
+  if (mouse_capture_target_.target &&
+      event->type != blink::WebInputEvent::MouseDown &&
+      (event->type == blink::WebInputEvent::MouseUp ||
+       event->modifiers & mouse_button_modifiers)) {
+    target = mouse_capture_target_.target;
+    transformed_point = root_view->TransformPointToCoordSpaceForView(
+        gfx::Point(event->x, event->y), target);
+    if (event->type == blink::WebInputEvent::MouseUp)
+      mouse_capture_target_.target = nullptr;
+  } else {
+    target = FindEventTarget(root_view, gfx::Point(event->x, event->y),
+                             &transformed_point);
+  }
+
+  if (event->type == blink::WebInputEvent::MouseDown)
+    mouse_capture_target_.target = target;
+
   if (!target)
     return;
 
   // SendMouseEnterOrLeaveEvents is called with the original event
   // coordinates, which are transformed independently for each view that will
   // receive an event.
   if ((event->type == blink::WebInputEvent::MouseLeave ||
        event->type == blink::WebInputEvent::MouseMove) &&
       target != last_mouse_move_target_)
     SendMouseEnterOrLeaveEvents(event, target, root_view);
@@ skipping 501 matching lines @@
   if (!touchpad_gesture_target_.target)
     return;
 
   // TODO(mohsen): Add tests to check event location.
   event->x += touchpad_gesture_target_.delta.x();
   event->y += touchpad_gesture_target_.delta.y();
   touchpad_gesture_target_.target->ProcessGestureEvent(*event, latency);
 }
 
 }  // namespace content