[Ozone-GBM] Handle GPU crashes

ui/ozone/platform/dri/gpu_platform_support_host_gbm.h

Index: ui/ozone/platform/dri/gpu_platform_support_host_gbm.h
diff --git a/ui/ozone/platform/dri/gpu_platform_support_host_gbm.h b/ui/ozone/platform/dri/gpu_platform_support_host_gbm.h
index 4887bae5b4e485fea0eb059301b528c1c1fce998..2e6c36000edc6b02fad8705956d6825d0775dd02 100644
--- a/ui/ozone/platform/dri/gpu_platform_support_host_gbm.h
+++ b/ui/ozone/platform/dri/gpu_platform_support_host_gbm.h
@@ -8,6 +8,7 @@
 #include <queue>
 #include <vector>
 
+#include "base/observer_list.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/platform/dri/hardware_cursor_delegate.h"
 #include "ui/ozone/public/gpu_platform_support_host.h"
@@ -20,6 +21,8 @@ class Point;
 
 namespace ui {
 
+class ChannelObserver;
+
 class GpuPlatformSupportHostGbm : public GpuPlatformSupportHost,
                                   public HardwareCursorDelegate,
                                   public IPC::Sender {
@@ -30,6 +33,9 @@ class GpuPlatformSupportHostGbm : public GpuPlatformSupportHost,
   void RegisterHandler(GpuPlatformSupportHost* handler);
   void UnregisterHandler(GpuPlatformSupportHost* handler);
 
+  void AddChannelObserver(ChannelObserver* observer);
+  void RemoveChannelObserver(ChannelObserver* observer);
+
   // GpuPlatformSupportHost:
   virtual void OnChannelEstablished(int host_id, IPC::Sender* sender) OVERRIDE;
   virtual void OnChannelDestroyed(int host_id) OVERRIDE;
@@ -55,6 +61,7 @@ class GpuPlatformSupportHostGbm : public GpuPlatformSupportHost,
   // delay sending them until the channel is created. These messages are stored
   // in |queued_messaged_|.
   std::queue<IPC::Message*> queued_messages_;
+  ObserverList<ChannelObserver> channel_observers_;
 };
 
 }  // namespace ui