Flush errors when destroying a passthrough command decoder.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
index ee25a045d89c983c3e2654c070ab45b51f25e3c6..731cf38be736a4630dffae9e7a0ea5923ee95ec1 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
@@ -208,6 +208,10 @@ bool GLES2DecoderPassthroughImpl::Initialize(
 }
 
 void GLES2DecoderPassthroughImpl::Destroy(bool have_context) {
+  if (have_context) {
+    FlushErrors();
+  }
+
   image_manager_.reset();
 
   DeleteServiceObjects(