Do not interchange MOUSE_MOVED and MOUSE_DRAGGED events in Widget

In Widget::OnMouseEvent(), do not handle MOUSE_MOVED
events as MOUSE_DRAGGED events, and do not handle
MOUSE_DRAGGED events as MOUSE_MOVED events; instead
trust that the mouse event type has been set correctly
before arriving at Widget. This also allows us to
remove the member |is_mouse_button_pressed_|
from Widget.

BUG=412929, 412931
TEST=WidgetTest.DragIntoView, WidgetTest.DragOutOfView

Review URL: https://codereview.chromium.org/560053002

Cr-Commit-Position: refs/heads/master@{#297215}

ui/views/view_unittest.cc

@@ -368,7 +368,7 @@ TEST_F(ViewTest, MouseEvent) {
   v2->Reset();
   ui::MouseEvent released(ui::ET_MOUSE_RELEASED, gfx::Point(), gfx::Point(), 0,
                           0);
-  root->OnMouseDragged(released);
+  root->OnMouseReleased(released);
   EXPECT_EQ(v2->last_mouse_event_type_, ui::ET_MOUSE_RELEASED);
   EXPECT_EQ(v2->location_.x(), -100);
   EXPECT_EQ(v2->location_.y(), -100);

ui/views/widget/root_view.cc

@@ -429,6 +429,7 @@ bool RootView::OnMousePressed(const ui::MouseEvent& event) {
 }
 
 bool RootView::OnMouseDragged(const ui::MouseEvent& event) {
+  CHECK_EQ(ui::ET_MOUSE_DRAGGED, event.type());
   if (mouse_pressed_handler_) {
     SetMouseLocationAndFlags(event);
 
@@ -486,6 +487,7 @@ void RootView::OnMouseCaptureLost() {
 }
 
 void RootView::OnMouseMoved(const ui::MouseEvent& event) {
+  CHECK_EQ(ui::ET_MOUSE_MOVED, event.type());
   View* v = GetEventHandlerForPoint(event.location());
   // Find the first enabled view, or the existing move handler, whichever comes
   // first.  The check for the existing handler is because if a view becomes

ui/views/widget/widget.cc

@@ -168,7 +168,6 @@ Widget::Widget()
       is_top_level_(false),
       native_widget_initialized_(false),
       native_widget_destroyed_(false),
-      is_mouse_button_pressed_(false),
       ignore_capture_loss_(false),
       last_mouse_event_was_move_(false),
       auto_release_capture_(true),
@@ -351,10 +350,6 @@ void Widget::Init(const InitParams& in_params) {
                    AsNativeWidgetPrivate();
   root_view_.reset(CreateRootView());
   default_theme_provider_.reset(new ui::DefaultThemeProvider);
-  if (params.type == InitParams::TYPE_MENU) {
-    is_mouse_button_pressed_ =
-        internal::NativeWidgetPrivate::IsMouseButtonDown();
-  }
   native_widget_->InitNativeWidget(params);
   if (RequiresNonClientView(params.type)) {
     non_client_view_ = new NonClientView;
@@ -948,8 +943,6 @@ void Widget::SetCapture(View* view) {
       return;
   }
 
-  if (internal::NativeWidgetPrivate::IsMouseButtonDown())
-    is_mouse_button_pressed_ = true;
   root_view_->SetMouseHandler(view);
 }
 
@@ -1190,11 +1183,12 @@ void Widget::OnKeyEvent(ui::KeyEvent* event) {
 //                   RootView from anywhere in Widget. Use
 //                   SendEventToProcessor() instead. See crbug.com/348087.
 void Widget::OnMouseEvent(ui::MouseEvent* event) {
+  if (event->type() != ui::ET_MOUSE_MOVED)
+    last_mouse_event_was_move_ = false;
+
   View* root_view = GetRootView();
   switch (event->type()) {
     case ui::ET_MOUSE_PRESSED: {
-      last_mouse_event_was_move_ = false;
-
       // We may get deleted by the time we return from OnMousePressed. So we
       // use an observer to make sure we are still alive.
       WidgetDeletionObserver widget_deletion_observer(this);
@@ -1212,7 +1206,6 @@ void Widget::OnMouseEvent(ui::MouseEvent* event) {
       if (root_view && root_view->OnMousePressed(*event) &&
           widget_deletion_observer.IsWidgetAlive() && IsVisible() &&
           internal::NativeWidgetPrivate::IsMouseButtonDown()) {
-        is_mouse_button_pressed_ = true;
         if (!native_widget_->HasCapture())
           native_widget_->SetCapture();
         event->SetHandled();
@@ -1221,8 +1214,6 @@ void Widget::OnMouseEvent(ui::MouseEvent* event) {
     }
 
     case ui::ET_MOUSE_RELEASED:
-      last_mouse_event_was_move_ = false;
-      is_mouse_button_pressed_ = false;
       // Release capture first, to avoid confusion if OnMouseReleased blocks.
       if (auto_release_capture_ && native_widget_->HasCapture()) {
         base::AutoReset<bool> resetter(&ignore_capture_loss_, true);
@@ -1235,13 +1226,8 @@ void Widget::OnMouseEvent(ui::MouseEvent* event) {
       return;
 
     case ui::ET_MOUSE_MOVED:
-    case ui::ET_MOUSE_DRAGGED:
-      if (native_widget_->HasCapture() && is_mouse_button_pressed_) {
-        last_mouse_event_was_move_ = false;
-        if (root_view)
-          root_view->OnMouseDragged(*event);
-      } else if (!last_mouse_event_was_move_ ||
-                 last_mouse_event_position_ != event->location()) {
+      if (!last_mouse_event_was_move_ ||
+          last_mouse_event_position_ != event->location()) {
         last_mouse_event_position_ = event->location();
         last_mouse_event_was_move_ = true;
         if (root_view)
@@ -1249,8 +1235,12 @@ void Widget::OnMouseEvent(ui::MouseEvent* event) {
       }
       return;
 
+    case ui::ET_MOUSE_DRAGGED:
+      if (root_view)
+        root_view->OnMouseDragged(*event);
+      return;
+
     case ui::ET_MOUSE_EXITED:
-      last_mouse_event_was_move_ = false;
       if (root_view)
         root_view->OnMouseExited(*event);
       return;
@@ -1273,7 +1263,6 @@ void Widget::OnMouseCaptureLost() {
   View* root_view = GetRootView();
   if (root_view)
     root_view->OnMouseCaptureLost();
-  is_mouse_button_pressed_ = false;
 }
 
 void Widget::OnScrollEvent(ui::ScrollEvent* event) {

ui/views/widget/widget.h

@@ -920,17 +920,13 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   // Whether native widget has been destroyed.
   bool native_widget_destroyed_;
 
-  // TODO(beng): Remove NativeWidgetGtk's dependence on these:
-  // If true, the mouse is currently down.
-  bool is_mouse_button_pressed_;
-
   // True if capture losses should be ignored.
   bool ignore_capture_loss_;
 
-  // TODO(beng): Remove NativeWidgetGtk's dependence on these:
   // The following are used to detect duplicate mouse move events and not
   // deliver them. Displaying a window may result in the system generating
   // duplicate move events even though the mouse hasn't moved.
+  // TODO(tdanderson): We may be able to remove these members.
   bool last_mouse_event_was_move_;
   gfx::Point last_mouse_event_position_;
 

ui/views/widget/widget_unittest.cc

@@ -3193,6 +3193,84 @@ TEST_F(WidgetTest, MouseEventTypesViaGenerator) {
   widget->CloseNow();
 }
 
+// Tests that a view does not receive entered, dragged, or moved events if
+// a mouse cursor is moved into it while the left mouse button is pressed.
+TEST_F(WidgetTest, DragIntoView) {
+  EventCountView* container = new EventCountView;
+  container->SetBounds(0, 0, 100, 80);
+
+  EventCountView* consume_view = new EventCountView;
+  consume_view->set_handle_mode(EventCountView::CONSUME_EVENTS);
+  consume_view->SetBounds(10, 10, 50, 40);
+
+  Widget* widget = CreateTopLevelFramelessPlatformWidget();
+  widget->SetBounds(gfx::Rect(0, 0, 100, 80));
+  widget->SetContentsView(container);
+  container->AddChildView(consume_view);
+
+  widget->Show();
+
+  ui::test::EventGenerator generator(GetContext(), widget->GetNativeWindow());
+  generator.set_current_location(gfx::Point(75, 15));
+
+  generator.PressLeftButton();
+  generator.MoveMouseTo(gfx::Point(20, 20));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_ENTERED));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_DRAGGED));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_MOVED));
+
+  widget->CloseNow();
+}
+
+// Tests that a view receives the correct mouse events if a mouse cursor
+// is moved out of its bounds while the left mouse button is pressed.
+TEST_F(WidgetTest, DragOutOfView) {
+  EventCountView* container = new EventCountView;
+  container->SetBounds(0, 0, 100, 80);
+
+  EventCountView* consume_view = new EventCountView;
+  consume_view->set_handle_mode(EventCountView::CONSUME_EVENTS);
+  consume_view->SetBounds(10, 10, 50, 40);
+
+  Widget* widget = CreateTopLevelFramelessPlatformWidget();
+  widget->SetBounds(gfx::Rect(0, 0, 100, 80));
+  widget->SetContentsView(container);
+  container->AddChildView(consume_view);
+
+  widget->Show();
+
+  ui::test::EventGenerator generator(GetContext(), widget->GetNativeWindow());
+  generator.set_current_location(gfx::Point(20, 20));
+
+  generator.PressLeftButton();
+  EXPECT_EQ(1, consume_view->GetEventCount(ui::ET_MOUSE_PRESSED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_PRESSED));
+  consume_view->ResetCounts();
+
+  generator.MoveMouseTo(gfx::Point(70, 70));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_EXITED));
+  EXPECT_EQ(1, consume_view->GetEventCount(ui::ET_MOUSE_DRAGGED));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_MOVED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_ENTERED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_DRAGGED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_MOVED));
+  consume_view->ResetCounts();
+
+  generator.MoveMouseTo(gfx::Point(71, 71));
+  EXPECT_EQ(1, consume_view->GetEventCount(ui::ET_MOUSE_DRAGGED));
+  EXPECT_EQ(0, consume_view->GetEventCount(ui::ET_MOUSE_MOVED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_DRAGGED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_MOVED));
+  consume_view->ResetCounts();
+
+  generator.ReleaseLeftButton();
+  EXPECT_EQ(1, consume_view->GetEventCount(ui::ET_MOUSE_RELEASED));
+  EXPECT_EQ(0, container->GetEventCount(ui::ET_MOUSE_RELEASED));
+  consume_view->ResetCounts();
+
+  widget->CloseNow();
+}
+
 // Tests that the root view is correctly set up for Widget types that do not
 // require a non-client view, before any other views are added to the widget.
 // That is, before Widget::ReorderNativeViews() is called which, if called with