Add support for new scroll valuators coming from CMT

ui/base/x/events_x.cc

Index: ui/base/x/events_x.cc
diff --git a/ui/base/x/events_x.cc b/ui/base/x/events_x.cc
index 4f2db853d7cb08892f4f8cb9a49e6dc114fc288a..1ccec4b1a5bbc6e1740e11c12586d374ccb60f26 100644
--- a/ui/base/x/events_x.cc
+++ b/ui/base/x/events_x.cc
@@ -11,6 +11,7 @@
 #include "base/logging.h"
 #include "ui/base/keycodes/keyboard_code_conversion_x.h"
 #include "ui/base/touch/touch_factory.h"
+#include "ui/base/x/scroll_factory.h"
 #include "ui/base/x/x11_util.h"
 #include "ui/gfx/point.h"
 
@@ -192,21 +193,22 @@ EventType EventTypeFromNative(const base::NativeEvent& native_event) {
           static_cast<XIDeviceEvent*>(native_event->xcookie.data);
       if (TouchFactory::GetInstance()->IsTouchDevice(xievent->sourceid))
         return GetTouchEventType(native_event);
-      int button = EventButtonFromNative(native_event);
       switch (xievent->evtype) {
         case XI_ButtonPress:
-          if (button >= kMinWheelButton &&
-              button <= kMaxWheelButton)
-            return ET_MOUSEWHEEL;
-          return ET_MOUSE_PRESSED;
-        case XI_ButtonRelease:
-          if (button >= kMinWheelButton &&
-              button <= kMaxWheelButton)
+        case XI_ButtonRelease: {
+          int button = EventButtonFromNative(native_event);
+          if (button >= kMinWheelButton && button <= kMaxWheelButton)
             return ET_MOUSEWHEEL;
-          return ET_MOUSE_RELEASED;
+          return xievent->evtype == XI_ButtonPress ?
+              ET_MOUSE_PRESSED : ET_MOUSE_RELEASED;
+        }
         case XI_Motion:
-          return GetButtonMaskForX2Event(xievent) ?
-              ET_MOUSE_DRAGGED : ET_MOUSE_MOVED;
+          if (GetScrollOffsets(native_event, NULL, NULL))
+            return ET_SCROLL;
+          else if (GetButtonMaskForX2Event(xievent))
+            return ET_MOUSE_DRAGGED;
+          else
+            return ET_MOUSE_MOVED;
       }
     }
     default:
@@ -405,6 +407,13 @@ float GetTouchForce(const base::NativeEvent& native_event) {
   return force;
 }
 
+bool GetScrollOffsets(const base::NativeEvent& native_event,
+                      float* x_offset,
+                      float* y_offset) {
+  return ui::ScrollFactory::GetInstance()->GetScrollOffsets(
+      *native_event, x_offset, y_offset);
+}
+
 base::NativeEvent CreateNoopEvent() {
   static XEvent* noop = NULL;
   if (!noop) {