Get Clang revision from a file rather than grepping DEPS

Grepping the clang_revision line out of DEPS is ugly.  It requires
other repositories to use the File() syntax in their DEPS just to
get the chromium/src/DEPS file so that tools/clang/scripts/update.sh
can grep it.  File() is de facto deprecated and it's not supported by
the .DEPS.git conversion tools, so this is a barrier to converting
dependent repositories such as native_client, as well as being ugly.

Instead, just keep the Clang revision number in the script that uses it.

When this lands, http://code.google.com/p/chromium/wiki/UpdatingClang
must be updated to describe updating the tools/clang/scripts/update.sh script.

BUG= http://code.google.com/p/chromium/issues/detail?id=102682
TEST= ran tools/clang/scripts/update.sh successfully

R=thakis@chromium.org,nsylvain@google.com

Review URL: http://codereview.chromium.org/8438021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@108736 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -34,12 +34,6 @@ vars = {
   "v8_revision": "9637",
   "webrtc_revision": "883",
   "jsoncpp_revision": "246",
-
-  # Note: On most bots, clang is not checked out via DEPS but by
-  # tools/clang/scripts/update.sh. The script reads this line here.
-  # Do NOT CHANGE this if you don't know what you're doing -- see
-  # http://code.google.com/p/chromium/wiki/UpdatingClang
-  "clang_revision": "142926",
 }
 
 deps = {

tools/clang/scripts/update.sh

@@ -5,15 +5,14 @@
 
 # This script will check out llvm and clang into third_party/llvm and build it.
 
+# Do NOT CHANGE this if you don't know what you're doing -- see
+# http://code.google.com/p/chromium/wiki/UpdatingClang
+CLANG_REVISION=142926
+
 THIS_DIR="$(dirname "${0}")"
 LLVM_DIR="${THIS_DIR}/../../../third_party/llvm"
 LLVM_BUILD_DIR="${LLVM_DIR}/../llvm-build"
 CLANG_DIR="${LLVM_DIR}/tools/clang"
-DEPS_FILE="${THIS_DIR}/../../../DEPS"
-if [ -e "${THIS_DIR}/../../../chromium_deps/DEPS" ]; then
-  # For bare WebKit/chromium checkouts.
-  DEPS_FILE="${THIS_DIR}/../../../chromium_deps/DEPS"
-fi
 STAMP_FILE="${LLVM_BUILD_DIR}/cr_build_revision"
 
 # ${A:-a} returns $A if it's set, a else.
@@ -85,11 +84,6 @@ if [[ "${OS}" = "Darwin" ]] && xcodebuild -version | grep -q 'Xcode 3.2' ; then
 fi
 
 
-# Since people need to run this script anyway to compile clang, let it check out
-# clang as well if it's not in DEPS, so that people don't have to change their
-# DEPS if they just want to give clang a try.
-CLANG_REVISION=$(grep 'clang_revision":' "${DEPS_FILE}" | egrep -o [[:digit:]]+)
-
 # Check if there's anything to be done, exit early if not.
 if [ -f "${STAMP_FILE}" ]; then
   PREVIOUSLY_BUILT_REVISON=$(cat "${STAMP_FILE}")
@@ -155,24 +149,16 @@ if [ -z "$force_local_build" ]; then
   fi
 fi
 
-if grep -q 'src/third_party/llvm":' "${DEPS_FILE}"; then
-  echo LLVM pulled in through DEPS, skipping LLVM update step
-else
-  echo Getting LLVM r"${CLANG_REVISION}" in "${LLVM_DIR}"
-  if ! svn co --force "${LLVM_REPO_URL}/llvm/trunk@${CLANG_REVISION}" \
-                      "${LLVM_DIR}"; then
-    echo Checkout failed, retrying
-    rm -rf "${LLVM_DIR}"
-    svn co --force "${LLVM_REPO_URL}/llvm/trunk@${CLANG_REVISION}" "${LLVM_DIR}"
-  fi
+echo Getting LLVM r"${CLANG_REVISION}" in "${LLVM_DIR}"
+if ! svn co --force "${LLVM_REPO_URL}/llvm/trunk@${CLANG_REVISION}" \
+                    "${LLVM_DIR}"; then
+  echo Checkout failed, retrying
+  rm -rf "${LLVM_DIR}"
+  svn co --force "${LLVM_REPO_URL}/llvm/trunk@${CLANG_REVISION}" "${LLVM_DIR}"
 fi
 
-if grep -q 'src/third_party/llvm/tools/clang":' "${DEPS_FILE}"; then
-  echo clang pulled in through DEPS, skipping clang update step
-else
-  echo Getting clang r"${CLANG_REVISION}" in "${CLANG_DIR}"
-  svn co --force "${LLVM_REPO_URL}/cfe/trunk@${CLANG_REVISION}" "${CLANG_DIR}"
-fi
+echo Getting clang r"${CLANG_REVISION}" in "${CLANG_DIR}"
+svn co --force "${LLVM_REPO_URL}/cfe/trunk@${CLANG_REVISION}" "${CLANG_DIR}"
 
 # Echo all commands.
 set -x