Complete disable_gl_rgb_format workaround for Mali-400 GPU

gpu/command_buffer/service/context_state.cc

Index: gpu/command_buffer/service/context_state.cc
diff --git a/gpu/command_buffer/service/context_state.cc b/gpu/command_buffer/service/context_state.cc
index 893465dc7250970c498fe2db8525e5713f137293..88ea9afa53d28fa1051c54a1b50785ac4d2fbac7 100644
--- a/gpu/command_buffer/service/context_state.cc
+++ b/gpu/command_buffer/service/context_state.cc
@@ -205,6 +205,7 @@ ContextState::ContextState(FeatureInfo* feature_info,
       pack_reverse_row_order(false),
       ignore_cached_state(false),
       fbo_binding_for_scissor_workaround_dirty(false),
+      emulating_rgb_with_rgba(false),
       feature_info_(feature_info),
       error_state_(ErrorState::Create(error_state_client, logger)) {
   Initialize();