touch: Fix wheel scrolling for xinput2.

BUG=wheel scrolling doesn't work
TEST=wheel scrolling scrolls the page when possible

Review URL: http://codereview.chromium.org/6250195

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74076 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 22 insertions, 2 deletions

diff --git a/views/event_x.cc b/views/event_x.cc
index c9ead16..dddcd2f 100644
--- a/views/event_x.cc
+++ b/views/event_x.cc
@@ -17,6 +17,9 @@ namespace views {
 
 namespace {
 
+// Scroll amount for each wheelscroll event. 53 is also the value used for GTK+.
+static int kWheelScrollAmount = 53;
+
 int GetEventFlagsFromXState(unsigned int state) {
   int flags = 0;
   if (state & ControlMask)
@@ -113,6 +116,16 @@ int GetTouchIDFromXEvent(XEvent* xev) {
 
 #endif  // HAVE_XINPUT2
 
+int GetMouseWheelOffset(XEvent* xev) {
+#if defined(HAVE_XINPUT2)
+  if (xev->type == GenericEvent) {
+    XIDeviceEvent* xiev = static_cast<XIDeviceEvent*>(xev->xcookie.data);
+    return xiev->detail == 4 ? kWheelScrollAmount : -kWheelScrollAmount;
+  }
+#endif
+  return xev->xbutton.button == 4 ? kWheelScrollAmount : -kWheelScrollAmount;
+}
+
 Event::EventType GetMouseEventType(XEvent* xev) {
   switch (xev->type) {
     case ButtonPress:
@@ -219,8 +232,7 @@ MouseWheelEvent::MouseWheelEvent(XEvent* xev)
     : LocatedEvent(Event::ET_MOUSEWHEEL,
                    GetMouseEventLocation(xev),
                    GetEventFlagsFromXState(xev->xbutton.state)),
-      offset_(xev->xbutton.button == 4 ? 53 : -53) {  // '53' is also the value
-                                                      // used for GTK+.
+      offset_(GetMouseWheelOffset(xev)) {
 }
 
 #if defined(HAVE_XINPUT2)
diff --git a/views/focus/accelerator_handler_touch.cc b/views/focus/accelerator_handler_touch.cc
index 4532034f..9847beb 100644
--- a/views/focus/accelerator_handler_touch.cc
+++ b/views/focus/accelerator_handler_touch.cc
@@ -87,6 +87,14 @@ bool DispatchX2Event(RootView* root, XEvent* xev) {
     case XI_ButtonPress:
     case XI_ButtonRelease:
     case XI_Motion: {
+      // Scrolling the wheel generates press/release events with button id's 4
+      // and 5. In case of a wheelscroll, we do not want to show the cursor.
+      XIDeviceEvent* xievent = static_cast<XIDeviceEvent*>(cookie->data);
+      if (xievent->detail == 4 || xievent->detail == 5) {
+        MouseWheelEvent wheelev(xev);
+        return root->ProcessMouseWheelEvent(wheelev);
+      }
+
       MouseEvent mouseev(xev);
       if (!touch_event) {
         // Show the cursor, and decide whether or not the cursor should be