Prevent plugins from changing mouse cursor during middle-click autoscroll.

third_party/WebKit/Source/core/page/AutoscrollController.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ skipping 220 matching lines @@
   const int x_signum = (distance.Width() < 0) ? -1 : (distance.Width() > 0);
   const int y_signum = (distance.Height() < 0) ? -1 : (distance.Height() > 0);
   FloatSize velocity(
       pow(fabs(distance.Width()), kExponent) * kMultiplier * x_signum,
       pow(fabs(distance.Height()), kExponent) * kMultiplier * y_signum);
 
   if (velocity != last_velocity_) {
     last_velocity_ = velocity;
     if (middle_click_mode_ == kMiddleClickInitial)
       middle_click_mode_ = kMiddleClickHolding;
+    page_->GetChromeClient().SetCursorOverridden(false);
     view->SetCursor(MiddleClickAutoscrollCursor(velocity));
+    page_->GetChromeClient().SetCursorOverridden(true);
     page_->GetChromeClient().AutoscrollFling(velocity, frame);
   }
 }
 
 void AutoscrollController::HandleMouseReleaseForMiddleClickAutoscroll(
     LocalFrame* frame,
     bool is_middle_button) {
   DCHECK(RuntimeEnabledFeatures::MiddleClickAutoscrollEnabled());
   if (!MiddleClickAutoscrollInProgress())
     return;
 
   if (!frame->IsMainFrame())
     return;
 
   if (middle_click_mode_ == kMiddleClickInitial && is_middle_button)
     middle_click_mode_ = kMiddleClickToggled;
   else if (middle_click_mode_ == kMiddleClickHolding)
     StopMiddleClickAutoscroll(frame);
 }
 
 void AutoscrollController::StopMiddleClickAutoscroll(LocalFrame* frame) {
   if (!MiddleClickAutoscrollInProgress())
     return;
 
   page_->GetChromeClient().AutoscrollEnd(frame);
   autoscroll_type_ = kNoAutoscroll;
+  page_->GetChromeClient().SetCursorOverridden(false);
   frame->LocalFrameRoot().GetEventHandler().ScheduleCursorUpdate();
 }
 
 bool AutoscrollController::MiddleClickAutoscrollInProgress() const {
   return autoscroll_type_ == kAutoscrollForMiddleClick;
 }
 
 void AutoscrollController::StartMiddleClickAutoscroll(
     LocalFrame* frame,
     const FloatPoint& position,
     const FloatPoint& position_global) {
   DCHECK(RuntimeEnabledFeatures::MiddleClickAutoscrollEnabled());
   // We don't want to trigger the autoscroll or the middleClickAutoscroll if
   // it's already active.
   if (autoscroll_type_ != kNoAutoscroll)
     return;
 
   autoscroll_type_ = kAutoscrollForMiddleClick;
   middle_click_mode_ = kMiddleClickInitial;
   middle_click_autoscroll_start_pos_global_ = position_global;
 
   UseCounter::Count(frame, WebFeature::kMiddleClickAutoscrollStart);
 
   last_velocity_ = FloatSize();
+
   if (LocalFrameView* view = frame->View())
     view->SetCursor(MiddleClickAutoscrollCursor(last_velocity_));
+  page_->GetChromeClient().SetCursorOverridden(true);
   page_->GetChromeClient().AutoscrollStart(
       position.ScaledBy(1 / frame->DevicePixelRatio()), frame);
 }
 
 void AutoscrollController::Animate(double) {
   // Middle-click autoscroll isn't handled on the main thread.
   if (MiddleClickAutoscrollInProgress())
     return;
 
   if (!autoscroll_layout_object_ || !autoscroll_layout_object_->GetFrame()) {
@@ skipping 28 matching lines @@
       break;
   }
 }
 
 void AutoscrollController::ScheduleMainThreadAnimation() {
   page_->GetChromeClient().ScheduleAnimation(
       autoscroll_layout_object_->GetFrame()->View());
 }
 
 }  // namespace blink