Fix type mismatch in forward declarations of the DeviceEvent struct.

BUG=none
TEST=Built and ran unit tests.

Change-Id: I70d57e183575a5b78cea0f675f8a78b8f93466b9
Reviewed-on: https://gerrit.chromium.org/gerrit/13357
Reviewed-by: Thieu Le <thieule@chromium.org>
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
diff --git a/cros-disks-server-impl.h b/cros-disks-server-impl.h
index eaec989..c022e74 100644
--- a/cros-disks-server-impl.h
+++ b/cros-disks-server-impl.h
@@ -18,12 +18,13 @@
 namespace cros_disks {
 
 class ArchiveManager;
-class DeviceEvent;
 class DiskManager;
 class FormatManager;
 class MountManager;
 class Platform;
 
+struct DeviceEvent;
+
 // The d-bus server for the cros-disks daemon.
 //
 // Example Usage:
diff --git a/device-event-dispatcher-interface.h b/device-event-dispatcher-interface.h
index b114f46..7b1414b 100644
--- a/device-event-dispatcher-interface.h
+++ b/device-event-dispatcher-interface.h
@@ -9,7 +9,7 @@
 
 namespace cros_disks {
 
-class DeviceEvent;
+struct DeviceEvent;
 
 // An interface class for dispatching device events.
 class DeviceEventDispatcherInterface {
diff --git a/device-event-moderator.h b/device-event-moderator.h
index 78c17c8..ca79085 100644
--- a/device-event-moderator.h
+++ b/device-event-moderator.h
@@ -15,7 +15,6 @@
 
 namespace cros_disks {
 
-class DeviceEvent;
 class DeviceEventDispatcherInterface;
 class DeviceEventSourceInterface;