Return false if IPC isn't handled by OverlayManager

ui/ozone/platform/drm/host/drm_overlay_manager.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/ozone/platform/drm/host/drm_overlay_manager.h"
 
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/ozone/common/gpu/ozone_gpu_messages.h"
 #include "ui/ozone/platform/drm/host/drm_gpu_platform_support_host.h"
 #include "ui/ozone/platform/drm/host/drm_overlay_candidates_host.h"
@@ skipping 24 matching lines @@
   core_->ResetCache();
 }
 
 void DrmOverlayManager::OnChannelDestroyed(int host_id) {}
 
 bool DrmOverlayManager::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(DrmOverlayManager, message)
     IPC_MESSAGE_HANDLER(OzoneHostMsg_OverlayCapabilitiesReceived,
                         OnOverlayResult)
+    IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void DrmOverlayManager::ResetCache() {
   core_->ResetCache();
 }
 
 void DrmOverlayManager::OnOverlayResult(
     gfx::AcceleratedWidget widget,
@@ skipping 22 matching lines @@
 }
 
 bool DrmOverlayManager::OverlayCandidatesIPC::CheckOverlayCapabilities(
     gfx::AcceleratedWidget widget,
     const std::vector<OverlayCheck_Params>& new_params) {
   return platform_support_->Send(
       new OzoneGpuMsg_CheckOverlayCapabilities(widget, new_params));
 }
 
 }  // namespace ui