skia/trunk changes for generic sanitizer gyp flag.

tools/xsan_build

+#!/bin/bash
+
+# Build Skia with one of Clang's many sanitizers.
+#
+# $ tools/xsan_build {address,thread,undefined,etc.} [any other flags to pass to make/ninja...]
+#
+# This script assumes the use of Clang >=3.2.
+#
+# For more information, see:
+#   http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation
+
+set -e
+
+sanitizer=$1
+shift
+args="$@"
+
+export CC="$(which clang)"
+export CXX="$(which clang++)"
+export LINK="$(which clang)"
+
+if [[ -z "${CC}" ]] || [[ -z "${CXX}" ]] || [[ -z "${LINK}" ]]; then
+  echo "Couldn't find Clang on this machine!"
+  exit 1
+fi
+
+export GYP_DEFINES="skia_sanitizer=$sanitizer ${GYP_DEFINES}"
+
+./gyp_skia
+if [[ $GYP_GENERATORS == "ninja" ]]; then
+    ninja ${args}
+else
+    make ${args}
+fi