wayland: fix MouseEvent flags

WaylandPointer was supplying the complete set of flags to MouseEvent
rather than the button that actually changed.

BUG=none
TEST=covered by test

Change-Id: Ib44585549d67001fdab847205819cea4cd646544
Reviewed-on: https://chromium-review.googlesource.com/996924Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548468}

ui/ozone/platform/wayland/wayland_pointer.cc

@@ -92,22 +92,22 @@ void WaylandPointer::Button(void* data,
                             uint32_t button,
                             uint32_t state) {
   WaylandPointer* pointer = static_cast<WaylandPointer*>(data);
-  int flag;
+  int changed_button;
   switch (button) {
     case BTN_LEFT:
-      flag = EF_LEFT_MOUSE_BUTTON;
+      changed_button = EF_LEFT_MOUSE_BUTTON;
       break;
     case BTN_MIDDLE:
-      flag = EF_MIDDLE_MOUSE_BUTTON;
+      changed_button = EF_MIDDLE_MOUSE_BUTTON;
       break;
     case BTN_RIGHT:
-      flag = EF_RIGHT_MOUSE_BUTTON;
+      changed_button = EF_RIGHT_MOUSE_BUTTON;
       break;
     case BTN_BACK:
-      flag = EF_BACK_MOUSE_BUTTON;
+      changed_button = EF_BACK_MOUSE_BUTTON;
       break;
     case BTN_FORWARD:
-      flag = EF_FORWARD_MOUSE_BUTTON;
+      changed_button = EF_FORWARD_MOUSE_BUTTON;
       break;
     default:
       return;
@@ -116,17 +116,19 @@ void WaylandPointer::Button(void* data,
   EventType type;
   if (state == WL_POINTER_BUTTON_STATE_PRESSED) {
     type = ET_MOUSE_PRESSED;
-    pointer->flags_ |= flag;
+    pointer->flags_ |= changed_button;
     pointer->connection_->set_serial(serial);
   } else {
     type = ET_MOUSE_RELEASED;
-    pointer->flags_ &= ~flag;
+    pointer->flags_ &= ~changed_button;
   }
 
-  int flags = pointer->GetFlagsWithKeyboardModifiers() | flag;
+  // MouseEvent's flags should contain the button that was released too.
+  const int flags = pointer->GetFlagsWithKeyboardModifiers() | changed_button;
   MouseEvent event(type, gfx::Point(), gfx::Point(),
                    base::TimeTicks() + base::TimeDelta::FromMilliseconds(time),
-                   flags, flag);
+                   flags, changed_button);
+
   event.set_location_f(pointer->location_);
   event.set_root_location_f(pointer->location_);
   pointer->callback_.Run(&event);

ui/ozone/platform/wayland/wayland_pointer_unittest.cc

@@ -122,27 +122,42 @@ TEST_P(WaylandPointerTest, MotionDragged) {
 TEST_P(WaylandPointerTest, ButtonPress) {
   wl_pointer_send_enter(pointer_->resource(), 1, surface_->resource(),
                         wl_fixed_from_int(200), wl_fixed_from_int(150));
+  Sync();
+
   wl_pointer_send_button(pointer_->resource(), 2, 1002, BTN_RIGHT,
                          WL_POINTER_BUTTON_STATE_PRESSED);
-
+  std::unique_ptr<Event> right_press_event;
+  EXPECT_CALL(delegate_, DispatchEvent(_))
+      .WillOnce(CloneEvent(&right_press_event));
   Sync();
-
-  std::unique_ptr<Event> event;
-  EXPECT_CALL(delegate_, DispatchEvent(_)).WillOnce(CloneEvent(&event));
+  ASSERT_TRUE(right_press_event);
+  ASSERT_TRUE(right_press_event->IsMouseEvent());
+  auto* right_press_mouse_event = right_press_event->AsMouseEvent();
+  EXPECT_EQ(ET_MOUSE_PRESSED, right_press_mouse_event->type());
+  EXPECT_EQ(EF_RIGHT_MOUSE_BUTTON, right_press_mouse_event->button_flags());
+  EXPECT_EQ(EF_RIGHT_MOUSE_BUTTON,
+            right_press_mouse_event->changed_button_flags());
+
+  std::unique_ptr<Event> left_press_event;
+  EXPECT_CALL(delegate_, DispatchEvent(_))
+      .WillOnce(CloneEvent(&left_press_event));
   wl_pointer_send_button(pointer_->resource(), 3, 1003, BTN_LEFT,
                          WL_POINTER_BUTTON_STATE_PRESSED);
 
   Sync();
 
-  ASSERT_TRUE(event);
-  ASSERT_TRUE(event->IsMouseEvent());
-  auto* mouse_event = event->AsMouseEvent();
-  EXPECT_EQ(ET_MOUSE_PRESSED, mouse_event->type());
+  ASSERT_TRUE(left_press_event);
+  ASSERT_TRUE(left_press_event->IsMouseEvent());
+  auto* left_press_mouse_event = left_press_event->AsMouseEvent();
+  EXPECT_EQ(ET_MOUSE_PRESSED, left_press_mouse_event->type());
   EXPECT_EQ(EF_LEFT_MOUSE_BUTTON | EF_RIGHT_MOUSE_BUTTON,
-            mouse_event->button_flags());
-  EXPECT_EQ(EF_LEFT_MOUSE_BUTTON, mouse_event->changed_button_flags());
-  EXPECT_EQ(gfx::PointF(200, 150), mouse_event->location_f());
-  EXPECT_EQ(gfx::PointF(200, 150), mouse_event->root_location_f());
+            left_press_mouse_event->button_flags());
+  EXPECT_EQ(EF_LEFT_MOUSE_BUTTON,
+            left_press_mouse_event->changed_button_flags());
+  EXPECT_EQ(EF_LEFT_MOUSE_BUTTON,
+            left_press_mouse_event->changed_button_flags());
+  EXPECT_EQ(gfx::PointF(200, 150), left_press_mouse_event->location_f());
+  EXPECT_EQ(gfx::PointF(200, 150), left_press_mouse_event->root_location_f());
 }
 
 TEST_P(WaylandPointerTest, ButtonRelease) {