gpu: Pull some variables onto the stack in the decoder

gpu/command_buffer/service/common_decoder.cc

Index: gpu/command_buffer/service/common_decoder.cc
diff --git a/gpu/command_buffer/service/common_decoder.cc b/gpu/command_buffer/service/common_decoder.cc
index a15c496ddbc02aff45d906123df00dc6595d88a7..69e028694e5b2e034415143f64daf8b338d09c2f 100644
--- a/gpu/command_buffer/service/common_decoder.cc
+++ b/gpu/command_buffer/service/common_decoder.cc
@@ -282,7 +282,7 @@ error::Error CommonDecoder::HandleGetBucketStart(uint32_t immediate_data_size,
   uint8_t* data = NULL;
   if (data_memory_size != 0 || data_memory_id != 0 || data_memory_offset != 0) {
     data = GetSharedMemoryAs<uint8_t*>(
-        args.data_memory_id, args.data_memory_offset, args.data_memory_size);
+        args.data_memory_id, args.data_memory_offset, data_memory_size);

[piman, 2016/03/25 20:48:06]

nit: same with other arguments - let's make sure to read any |args| field
exactly once.

     if (!data) {
       return error::kInvalidArguments;
     }