[Ozone-GBM] Handle GPU crashes

ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc

Index: ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc
diff --git a/ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc b/ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc
index 160b5153dbd4df2eaddf55892c9c6fab5196251b..90a75ca52f67b582421218b925dd29d3dbecffe1 100644
--- a/ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc
+++ b/ui/ozone/platform/dri/gpu_platform_support_host_gbm.cc
@@ -7,6 +7,7 @@
 #include "base/debug/trace_event.h"
 #include "ui/ozone/common/gpu/ozone_gpu_message_params.h"
 #include "ui/ozone/common/gpu/ozone_gpu_messages.h"
+#include "ui/ozone/platform/dri/channel_observer.h"
 
 namespace ui {
 
@@ -29,6 +30,18 @@ void GpuPlatformSupportHostGbm::UnregisterHandler(
     handlers_.erase(it);
 }
 
+void GpuPlatformSupportHostGbm::AddChannelObserver(ChannelObserver* observer) {
+  channel_observers_.AddObserver(observer);
+
+  if (sender_)
+    observer->OnChannelEstablished();
+}
+
+void GpuPlatformSupportHostGbm::RemoveChannelObserver(
+    ChannelObserver* observer) {
+  channel_observers_.RemoveObserver(observer);
+}
+
 void GpuPlatformSupportHostGbm::OnChannelEstablished(int host_id,
                                                      IPC::Sender* sender) {
   TRACE_EVENT0("dri", "GpuPlatformSupportHostGbm::OnChannelEstablished");
@@ -42,6 +55,9 @@ void GpuPlatformSupportHostGbm::OnChannelEstablished(int host_id,
 
   for (size_t i = 0; i < handlers_.size(); ++i)
     handlers_[i]->OnChannelEstablished(host_id, sender);
+
+  FOR_EACH_OBSERVER(
+      ChannelObserver, channel_observers_, OnChannelEstablished());
 }
 
 void GpuPlatformSupportHostGbm::OnChannelDestroyed(int host_id) {
@@ -53,6 +69,8 @@ void GpuPlatformSupportHostGbm::OnChannelDestroyed(int host_id) {
 
   for (size_t i = 0; i < handlers_.size(); ++i)
     handlers_[i]->OnChannelDestroyed(host_id);
+
+  FOR_EACH_OBSERVER(ChannelObserver, channel_observers_, OnChannelDestroyed());
 }
 
 bool GpuPlatformSupportHostGbm::OnMessageReceived(const IPC::Message& message) {