views: Stop dispatching scroll-gesture events if the scroll-begin event wasn't handled.

ui/views/widget/widget_unittest.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/native_widget_types.h"
@@ skipping 118 matching lines @@
   virtual ~EventCountView() {}
 
   int GetEventCount(ui::EventType type) {
     return event_count_[type];
   }
 
   void ResetCounts() {
     event_count_.clear();
   }
 
- private:
-  void RecordEvent(const ui::Event& event) {
-    ++event_count_[event.type()];
-  }
-
+ protected:
   // Overridden from View:
   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE {
     RecordEvent(event);
     return false;
   }
   virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE {
     RecordEvent(event);
     return false;
   }
   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE {
@@ skipping 31 matching lines @@
   virtual void OnScrollEvent(ui::ScrollEvent* event) OVERRIDE {
     RecordEvent(*event);
   }
   virtual void OnTouchEvent(ui::TouchEvent* event) OVERRIDE {
     RecordEvent(*event);
   }
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
     RecordEvent(*event);
   }
 
+ private:
+  void RecordEvent(const ui::Event& event) {
+    ++event_count_[event.type()];
+  }
+
   std::map<ui::EventType, int> event_count_;
 
   DISALLOW_COPY_AND_ASSIGN(EventCountView);
 };
 
+// A view that keeps track of the events it receives, and consumes all scroll
+// gesture events.
+class ScrollableEventCountView : public EventCountView {
+ public:
+  ScrollableEventCountView() {}
+  virtual ~ScrollableEventCountView() {}
+
+ private:
+  // Overridden from ui::EventHandler:
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
+    EventCountView::OnGestureEvent(event);
+    switch (event->type()) {
+      case ui::ET_GESTURE_SCROLL_BEGIN:
+      case ui::ET_GESTURE_SCROLL_UPDATE:
+      case ui::ET_GESTURE_SCROLL_END:
+      case ui::ET_SCROLL_FLING_START:
+        event->SetHandled();
+        break;
+      default:
+        break;
+    }
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ScrollableEventCountView);
+};
+
 // A view that does a capture on gesture-begin events.
 class GestureCaptureView : public View {
  public:
   GestureCaptureView() {}
   virtual ~GestureCaptureView() {}
 
  private:
   // Overridden from View:
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
     if (event->type() == ui::ET_GESTURE_BEGIN) {
@@ skipping 1065 matching lines @@
   focused_view->ResetCounts();
   cursor_view->ResetCounts();
 
   ui::ScrollEvent scroll2(ui::ET_SCROLL, gfx::Point(5, 5), 0, 0, 20);
   widget->OnScrollEvent(&scroll2);
   EXPECT_EQ(1, focused_view->GetEventCount(ui::ET_SCROLL));
   EXPECT_EQ(1, focused_view->GetEventCount(ui::ET_MOUSEWHEEL));
 
   EXPECT_EQ(0, cursor_view->GetEventCount(ui::ET_SCROLL));
   EXPECT_EQ(0, cursor_view->GetEventCount(ui::ET_MOUSEWHEEL));
+
+  widget->CloseNow();
 }
 
 #endif  // defined(USE_AURA)
 
+// Tests that if a scroll-begin gesture is not handled, then subsequent scroll
+// events are not dispatched to any view.
+TEST_F(WidgetTest, GestureScrollEventDispatching) {
+  EventCountView* noscroll_view = new EventCountView;
+  EventCountView* scroll_view = new ScrollableEventCountView;
+
+  noscroll_view->SetBounds(0, 0, 50, 40);
+  scroll_view->SetBounds(60, 0, 40, 40);
+
+  Widget* widget = CreateTopLevelPlatformWidget();
+  widget->GetRootView()->AddChildView(noscroll_view);
+  widget->GetRootView()->AddChildView(scroll_view);
+
+  {
+    ui::GestureEvent begin(ui::ET_GESTURE_SCROLL_BEGIN,
+        5, 5, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_BEGIN, 0, 0),
+        1);
+    widget->OnGestureEvent(&begin);
+    ui::GestureEvent update(ui::ET_GESTURE_SCROLL_UPDATE,
+        25, 15, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_UPDATE, 20, 10),
+        1);
+    widget->OnGestureEvent(&update);
+    ui::GestureEvent end(ui::ET_GESTURE_SCROLL_END,
+        25, 15, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_END, 0, 0),
+        1);
+    widget->OnGestureEvent(&end);
+
+    EXPECT_EQ(1, noscroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_BEGIN));
+    EXPECT_EQ(0, noscroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_UPDATE));
+    EXPECT_EQ(0, noscroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_END));
+  }
+
+  {
+    ui::GestureEvent begin(ui::ET_GESTURE_SCROLL_BEGIN,
+        65, 5, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_BEGIN, 0, 0),
+        1);
+    widget->OnGestureEvent(&begin);
+    ui::GestureEvent update(ui::ET_GESTURE_SCROLL_UPDATE,
+        85, 15, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_UPDATE, 20, 10),
+        1);
+    widget->OnGestureEvent(&update);
+    ui::GestureEvent end(ui::ET_GESTURE_SCROLL_END,
+        85, 15, 0, base::TimeDelta(),
+        ui::GestureEventDetails(ui::ET_GESTURE_SCROLL_END, 0, 0),
+        1);
+    widget->OnGestureEvent(&end);
+
+    EXPECT_EQ(1, scroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_BEGIN));
+    EXPECT_EQ(1, scroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_UPDATE));
+    EXPECT_EQ(1, scroll_view->GetEventCount(ui::ET_GESTURE_SCROLL_END));
+  }
+
+  widget->CloseNow();
+}
+
 }  // namespace
 }  // namespace views