wayland-protocols: Add pointer_stylus_exists error to zcr_stylus_v1 interface.

This error is produced if get_pointer_stylus method is called with
a pointer object that is already associated with a pointer stylus
object.

BUG=673666

Review-Url: https://codereview.chromium.org/2575693002
Cr-Commit-Position: refs/heads/master@{#438985}

third_party/wayland-protocols/include/protocol/stylus-unstable-v1-client-protocol.h

@@ -106,6 +106,16 @@ extern const struct wl_interface zcr_stylus_v1_interface;
  */
 extern const struct wl_interface zcr_pointer_stylus_v1_interface;
 
+#ifndef ZCR_STYLUS_V1_ERROR_ENUM
+#define ZCR_STYLUS_V1_ERROR_ENUM
+enum zcr_stylus_v1_error {
+	/**
+	 * the pointer already has a pointer_stylus object associated
+	 */
+	ZCR_STYLUS_V1_ERROR_POINTER_STYLUS_EXISTS = 0,
+};
+#endif /* ZCR_STYLUS_V1_ERROR_ENUM */
+
 #define ZCR_STYLUS_V1_GET_POINTER_STYLUS	0
 
 /**
@@ -144,7 +154,8 @@ zcr_stylus_v1_destroy(struct zcr_stylus_v1 *zcr_stylus_v1)
  * @ingroup iface_zcr_stylus_v1
  *
  * Create pointer_stylus object. See zcr_pointer_stylus_v1 interface for
- * details.
+ * details. If the given wl_pointer already has a pointer_stylus object
+ * associated, the pointer_stylus_exists protocol error is raised.
  */
 static inline struct zcr_pointer_stylus_v1 *
 zcr_stylus_v1_get_pointer_stylus(struct zcr_stylus_v1 *zcr_stylus_v1, struct wl_pointer *pointer)

third_party/wayland-protocols/include/protocol/stylus-unstable-v1-server-protocol.h

@@ -109,6 +109,16 @@ extern const struct wl_interface zcr_stylus_v1_interface;
  */
 extern const struct wl_interface zcr_pointer_stylus_v1_interface;
 
+#ifndef ZCR_STYLUS_V1_ERROR_ENUM
+#define ZCR_STYLUS_V1_ERROR_ENUM
+enum zcr_stylus_v1_error {
+	/**
+	 * the pointer already has a pointer_stylus object associated
+	 */
+	ZCR_STYLUS_V1_ERROR_POINTER_STYLUS_EXISTS = 0,
+};
+#endif /* ZCR_STYLUS_V1_ERROR_ENUM */
+
 /**
  * @ingroup iface_zcr_stylus_v1
  * @struct zcr_stylus_v1_interface
@@ -118,7 +128,9 @@ struct zcr_stylus_v1_interface {
 	 * get stylus interface for pointer
 	 *
 	 * Create pointer_stylus object. See zcr_pointer_stylus_v1
-	 * interface for details.
+	 * interface for details. If the given wl_pointer already has a
+	 * pointer_stylus object associated, the pointer_stylus_exists
+	 * protocol error is raised.
 	 */
 	void (*get_pointer_stylus)(struct wl_client *client,
 				   struct wl_resource *resource,

third_party/wayland-protocols/protocol/stylus-protocol.c

@@ -43,7 +43,7 @@ static const struct wl_message zcr_stylus_v1_requests[] = {
 };
 
 WL_EXPORT const struct wl_interface zcr_stylus_v1_interface = {
-	"zcr_stylus_v1", 1,
+	"zcr_stylus_v1", 2,
 	1, zcr_stylus_v1_requests,
 	0, NULL,
 };

third_party/wayland-protocols/unstable/stylus/stylus-unstable-v1.xml

@@ -24,7 +24,7 @@
     DEALINGS IN THE SOFTWARE.
   </copyright>
 
-  <interface name="zcr_stylus_v1" version="1">
+  <interface name="zcr_stylus_v1" version="2">
     <description summary="extends wl_pointer with events for on-screen stylus">
       Allows a wl_pointer to represent an on-screen stylus. The client can
       interpret the on-screen stylus like any other mouse device, and use
@@ -44,10 +44,16 @@
       interface version number is reset.
     </description>
 
+    <enum name="error">
+      <entry name="pointer_stylus_exists" value="0"
+             summary="the pointer already has a pointer_stylus object associated"/>
+    </enum>
+
     <request name="get_pointer_stylus">
       <description summary="get stylus interface for pointer">
         Create pointer_stylus object. See zcr_pointer_stylus_v1 interface for
-        details.
+        details. If the given wl_pointer already has a pointer_stylus object
+        associated, the pointer_stylus_exists protocol error is raised.
       </description>
       <arg name="id" type="new_id" interface="zcr_pointer_stylus_v1"/>
       <arg name="pointer" type="object" interface="wl_pointer"/>