Use the TouchscreenDevice when looking up the size of the touch area

Removes some X11 dependencies when looking up the size of the
touchscreen.

BUG=425258

Review URL: https://codereview.chromium.org/683823004

Cr-Commit-Position: refs/heads/master@{#301713}

5 files changed, 26 insertions, 8 deletions

diff --git a/ui/events/input_device.cc b/ui/events/input_device.cc
index 4c35624..b170b4a 100644
--- a/ui/events/input_device.cc
+++ b/ui/events/input_device.cc
@@ -11,6 +11,10 @@ namespace ui {
 // static
 const unsigned int InputDevice::kInvalidId = 0;
 
+InputDevice::InputDevice()
+    : id(kInvalidId), type(InputDeviceType::INPUT_DEVICE_UNKNOWN) {
+}
+
 InputDevice::InputDevice(unsigned int id,
                          InputDeviceType type,
                          const std::string& name)
diff --git a/ui/events/input_device.h b/ui/events/input_device.h
index 526b005..83a0316 100644
--- a/ui/events/input_device.h
+++ b/ui/events/input_device.h
@@ -21,6 +21,9 @@ enum InputDeviceType {
 struct EVENTS_BASE_EXPORT InputDevice {
   static const unsigned int kInvalidId;
 
+  // Creates an invalid input device.
+  InputDevice();
+
   InputDevice(unsigned int id, InputDeviceType type, const std::string& name);
   virtual ~InputDevice();
 
diff --git a/ui/events/touchscreen_device.cc b/ui/events/touchscreen_device.cc
index 58c2370d..28ba592 100644
--- a/ui/events/touchscreen_device.cc
+++ b/ui/events/touchscreen_device.cc
@@ -10,7 +10,10 @@
 
 namespace ui {
 
-TouchscreenDevice::TouchscreenDevice(int id,
+TouchscreenDevice::TouchscreenDevice() {
+}
+
+TouchscreenDevice::TouchscreenDevice(unsigned int id,
                                      InputDeviceType type,
                                      const std::string& name,
                                      const gfx::Size& size)
diff --git a/ui/events/touchscreen_device.h b/ui/events/touchscreen_device.h
index d281a0b..48cad35 100644
--- a/ui/events/touchscreen_device.h
+++ b/ui/events/touchscreen_device.h
@@ -15,7 +15,10 @@ namespace ui {
 
 // Represents a Touchscreen device state.
 struct EVENTS_BASE_EXPORT TouchscreenDevice : public InputDevice {
-  TouchscreenDevice(int id,
+  // Creates an invalid touchscreen device.
+  TouchscreenDevice();
+
+  TouchscreenDevice(unsigned int id,
                     InputDeviceType type,
                     const std::string& name,
                     const gfx::Size& size);
diff --git a/ui/events/x/hotplug_event_handler_x11.cc b/ui/events/x/hotplug_event_handler_x11.cc
index ae685f87..30dcfee 100644
--- a/ui/events/x/hotplug_event_handler_x11.cc
+++ b/ui/events/x/hotplug_event_handler_x11.cc
@@ -191,8 +191,8 @@ void HotplugEventHandlerX11::HandleTouchscreenDevices(
     if (!x11_devices[i].enabled || x11_devices[i].use != XIFloatingSlave)
       continue;  // Assume all touchscreens are floating slaves
 
-    double width = -1.0;
-    double height = -1.0;
+    double max_x = -1.0;
+    double max_y = -1.0;
     bool is_direct_touch = false;
 
     for (int j = 0; j < x11_devices[i].num_classes; j++) {
@@ -206,13 +206,13 @@ void HotplugEventHandlerX11::HandleTouchscreenDevices(
           // Ignore X axis valuator with unexpected properties
           if (valuator_info->number == 0 && valuator_info->mode == Absolute &&
               valuator_info->min == 0.0) {
-            width = valuator_info->max;
+            max_x = valuator_info->max;
           }
         } else if (valuator_y == valuator_info->label) {
           // Ignore Y axis valuator with unexpected properties
           if (valuator_info->number == 1 && valuator_info->mode == Absolute &&
               valuator_info->min == 0.0) {
-            height = valuator_info->max;
+            max_y = valuator_info->max;
           }
         }
       }
@@ -227,14 +227,19 @@ void HotplugEventHandlerX11::HandleTouchscreenDevices(
 
     // Touchscreens should have absolute X and Y axes, and be direct touch
     // devices.
-    if (width > 0.0 && height > 0.0 && is_direct_touch) {
+    if (max_x > 0.0 && max_y > 0.0 && is_direct_touch) {
       InputDeviceType type =
           IsTouchscreenInternal(display, x11_devices[i].deviceid)
               ? InputDeviceType::INPUT_DEVICE_INTERNAL
               : InputDeviceType::INPUT_DEVICE_EXTERNAL;
       std::string name(x11_devices[i].name);
+      // |max_x| and |max_y| are inclusive values, so we need to add 1 to get
+      // the size.
       devices.push_back(TouchscreenDevice(
-          x11_devices[i].deviceid, type, name, gfx::Size(width, height)));
+          x11_devices[i].deviceid,
+          type,
+          name,
+          gfx::Size(max_x + 1, max_y + 1)));
     }
   }