Hook up shader long variable name mapping with GPU command buffer port.

gpu/command_buffer/service/shader_translator.h

Index: gpu/command_buffer/service/shader_translator.h
===================================================================
--- gpu/command_buffer/service/shader_translator.h	(revision 87329)
+++ gpu/command_buffer/service/shader_translator.h	(working copy)
@@ -45,12 +45,14 @@
         : type(0),
           size(0) {
     }
-    VariableInfo(int _type, int _size)
+      VariableInfo(int _type, int _size, std::string _name)
         : type(_type),
-          size(_size) {
+          size(_size),
+          name(_name) {
     }
     int type;
     int size;
+    std::string name;  // name in the original shader source.
   };
   // Mapping between variable name and info.
   typedef base::hash_map<std::string, VariableInfo> VariableMap;