Reland of [Ozone] Properly initialize multitouch slot values

ui/events/ozone/evdev/event_device_info.h

Index: ui/events/ozone/evdev/event_device_info.h
diff --git a/ui/events/ozone/evdev/event_device_info.h b/ui/events/ozone/evdev/event_device_info.h
index 321711404d5c23c66cc8d347f1840e976b78bb60..adca89e09ce31c8b43dd23f5f2db442e1fed5266 100644
--- a/ui/events/ozone/evdev/event_device_info.h
+++ b/ui/events/ozone/evdev/event_device_info.h
@@ -8,10 +8,15 @@
 #include <limits.h>
 #include <linux/input.h>
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "ui/events/ozone/evdev/event_device_util.h"
 #include "ui/events/ozone/evdev/events_ozone_evdev_export.h"
 
+// ABS_MT_SLOT isn't valid options for EVIOCGMTSLOTS ioctl.
+#define EVDEV_ABS_MT_COUNT (ABS_MAX - ABS_MT_SLOT - 1)
+
 namespace ui {
 
 // Device information for Linux input devices
@@ -38,6 +43,7 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
   // Properties of absolute axes.
   int32 GetAbsMinimum(unsigned int code) const;
   int32 GetAbsMaximum(unsigned int code) const;
+  int32 GetSlotValue(unsigned int code, unsigned int slot) const;
 
   // Check input device properties.
   bool HasProp(unsigned int code) const;
@@ -53,6 +59,9 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
   bool IsMappedToScreen() const;
 
  private:
+  // Return the slot vector in |slot_values_| for |code|.
+  const std::vector<int32_t>& GetMtSlotsForCode(int code) const;
+
   unsigned long ev_bits_[EVDEV_BITS_TO_LONGS(EV_CNT)];
   unsigned long key_bits_[EVDEV_BITS_TO_LONGS(KEY_CNT)];
   unsigned long rel_bits_[EVDEV_BITS_TO_LONGS(REL_CNT)];
@@ -64,6 +73,9 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
 
   struct input_absinfo abs_info_[ABS_CNT];
 
+  // Store the values for the multi-touch properties for each slot.
+  std::vector<int32_t> slot_values_[EVDEV_ABS_MT_COUNT];
+
   DISALLOW_COPY_AND_ASSIGN(EventDeviceInfo);
 };