Mojom: Blanket change to mark all pointer/handle fields as nullable.

mojo/services/gles2/command_buffer.mojom

Index: mojo/services/gles2/command_buffer.mojom
diff --git a/mojo/services/gles2/command_buffer.mojom b/mojo/services/gles2/command_buffer.mojom
index faba8accc984dacc50be22ffd633f077aa2bc084..302dcf4c4ef0f01e6bb417eae8c80ffa3e55a7ff 100644
--- a/mojo/services/gles2/command_buffer.mojom
+++ b/mojo/services/gles2/command_buffer.mojom
@@ -16,18 +16,18 @@ struct CommandBufferState {
 
 interface CommandBufferSyncClient {
   DidInitialize(bool success);
-  DidMakeProgress(CommandBufferState state);
+  DidMakeProgress(CommandBufferState? state);
 };
 
 [Client=CommandBufferClient]
 interface CommandBuffer {
-  Initialize(CommandBufferSyncClient sync_client,
-             handle<shared_buffer> shared_state);
+  Initialize(CommandBufferSyncClient? sync_client,
+             handle<shared_buffer>? shared_state);
   SetGetBuffer(int32 buffer);
   Flush(int32 put_offset);
   MakeProgress(int32 last_get_offset);
   RegisterTransferBuffer(
-      int32 id, handle<shared_buffer> transfer_buffer, uint32 size);
+      int32 id, handle<shared_buffer>? transfer_buffer, uint32 size);
   DestroyTransferBuffer(int32 id);
   Echo() => ();