Cleanup: Pass std::string as const reference if possible

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 410f1cc09454b3a3ccb13b86d5adc6f76efde3e8..4ff246dfa55c73f95c5acf997c95fb79df0f2291 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1054,8 +1054,10 @@ class GLES2DecoderImpl : public GLES2Decoder,
   void DoProduceTextureCHROMIUM(GLenum target, const GLbyte* key);
   void DoProduceTextureDirectCHROMIUM(GLuint texture, GLenum target,
       const GLbyte* key);
-  void ProduceTextureRef(std::string func_name, TextureRef* texture_ref,
-      GLenum target, const GLbyte* data);
+  void ProduceTextureRef(const std::string& func_name,
+                         TextureRef* texture_ref,
+                         GLenum target,
+                         const GLbyte* data);
 
   void EnsureTextureForClientId(GLenum target, GLuint client_id);
   void DoConsumeTextureCHROMIUM(GLenum target, const GLbyte* key);
@@ -13836,8 +13838,10 @@ void GLES2DecoderImpl::DoProduceTextureDirectCHROMIUM(GLuint client_id,
       target, data);
 }
 
-void GLES2DecoderImpl::ProduceTextureRef(std::string func_name,
-    TextureRef* texture_ref, GLenum target, const GLbyte* data) {
+void GLES2DecoderImpl::ProduceTextureRef(const std::string& func_name,
+                                         TextureRef* texture_ref,
+                                         GLenum target,
+                                         const GLbyte* data) {
   const Mailbox& mailbox = *reinterpret_cast<const Mailbox*>(data);
   DLOG_IF(ERROR, !mailbox.Verify()) << func_name << " was passed a "
                                        "mailbox that was not generated by "