I recommend putting git-gse in your $PATH then search for occurences of strings $@ in your repo, pretty fast.

git-gse

#!/bin/sh
# Copyright (c) 2010 The Chromium Authors. All rights reserved.
# Copyright (c) 2013 Dominik Röttsches
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
git grep -n -e "$@" -- "*.h" "*.hpp" "*.cpp" "*.c" "*.cc" "*.cpp" "*.inl"\
   "*.grd" "*.idl" "*.m" "*.mm" "*.py" "*.sh" "*.cfg"\
   "*.vcproj" "*.vsprops" "*.make"\
   "*.gyp" "*.gypi" "*.js" "*.html" "*.css" "*.cmake" "*CMakeLists.txt"\
   "*GNUmakefile.*"\
   "*.edc"\
   "*Tools/Scripts/*"

Updated to remove scons, include edc and Tools/Scripts, after discussing with @tmpsantos.