Account for failure of coordinate space transformations in browser

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 164 matching lines @@
   RenderWidgetHostViewBase* target;
   gfx::Point 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 (!root_view->TransformPointToCoordSpaceForView(
+            gfx::Point(event->x, event->y), target, &transformed_point))
+      return;
     if (event->type == blink::WebInputEvent::MouseUp)
       mouse_capture_target_.target = nullptr;
   } else {
     target = FindEventTarget(root_view, gfx::Point(event->x, event->y),
                              &transformed_point);
   }
 
   // RenderWidgetHostViewGuest does not properly handle direct routing of mouse
   // events, so they have to go by the double-hop forwarding path through
   // the embedding renderer and then BrowserPluginGuest.
@@ skipping 225 matching lines @@
     common_ancestor = entered_views.back();
     entered_views.pop_back();
     exited_views.pop_back();
   }
 
   gfx::Point transformed_point;
   // Send MouseLeaves.
   for (auto view : exited_views) {
     blink::WebMouseEvent mouse_leave(*event);
     mouse_leave.type = blink::WebInputEvent::MouseLeave;
-    transformed_point = root_view->TransformPointToCoordSpaceForView(
-        gfx::Point(event->x, event->y), view);
+    // There is a chance of a race if the last target has recently created a
+    // new compositor surface. The SurfaceID for that might not have
+    // propagated to its embedding surface, which makes it impossible to
+    // compute the transformation for it
+    if (!root_view->TransformPointToCoordSpaceForView(
+            gfx::Point(event->x, event->y), view, &transformed_point))
+      transformed_point = gfx::Point();
     mouse_leave.x = transformed_point.x();
     mouse_leave.y = transformed_point.y();
     view->ProcessMouseEvent(mouse_leave, ui::LatencyInfo());
   }
 
   // The ancestor might need to trigger MouseOut handlers.
   if (common_ancestor && common_ancestor != target) {
     blink::WebMouseEvent mouse_move(*event);
     mouse_move.type = blink::WebInputEvent::MouseMove;
-    transformed_point = root_view->TransformPointToCoordSpaceForView(
-        gfx::Point(event->x, event->y), common_ancestor);
+    if (!root_view->TransformPointToCoordSpaceForView(
+            gfx::Point(event->x, event->y), common_ancestor,
+            &transformed_point))
+      transformed_point = gfx::Point();
     mouse_move.x = transformed_point.x();
     mouse_move.y = transformed_point.y();
     common_ancestor->ProcessMouseEvent(mouse_move, ui::LatencyInfo());
   }
 
   // Send MouseMoves to trigger MouseEnter handlers.
   for (auto view : entered_views) {
     if (view == target)
       continue;
     blink::WebMouseEvent mouse_enter(*event);
     mouse_enter.type = blink::WebInputEvent::MouseMove;
-    transformed_point = root_view->TransformPointToCoordSpaceForView(
-        gfx::Point(event->x, event->y), view);
+    if (!root_view->TransformPointToCoordSpaceForView(
+            gfx::Point(event->x, event->y), view, &transformed_point))
+      transformed_point = gfx::Point();
     mouse_enter.x = transformed_point.x();
     mouse_enter.y = transformed_point.y();
     view->ProcessMouseEvent(mouse_enter, ui::LatencyInfo());
   }
 
   last_mouse_move_target_ = target;
   last_mouse_move_root_view_ = root_view;
 }
 
 void RenderWidgetHostInputEventRouter::BubbleScrollEvent(
@@ skipping 271 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