Use UintToString for unsigned values in //gpu

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 805cd70a0838bd2f0dc35f069bb52d0c98cd2c8d..819388cacfff14b1d1d0b347d0c1db7acc7532a8 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -7158,11 +7158,11 @@ bool GLES2DecoderImpl::PrepareTexturesForRender() {
           if (!texture_ref) {
             LOCAL_RENDER_WARNING(
                 std::string("there is no texture bound to the unit ") +
-                base::IntToString(texture_unit_index));
+                base::UintToString(texture_unit_index));
           } else {
             LOCAL_RENDER_WARNING(
                 std::string("texture bound to texture unit ") +
-                base::IntToString(texture_unit_index) +
+                base::UintToString(texture_unit_index) +
                 " is not renderable. It maybe non-power-of-2 and have"
                 " incompatible texture filtering.");
           }