Update find_sdk.py to print out the toolchain bin dir.

This allows build scripts to directly specify the required binaries, rather than
implicitly relying on xcrun to find the binaries.

Bug: 971452
Change-Id: I02862dc39fba7ec1c7534283b0b5a5bfd5f4bbd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1648780Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667148}

build/config/mac/mac_sdk.gni

@@ -45,7 +45,10 @@ declare_args() {
 # iOS toolchains.
 _verify_sdk = is_chrome_branded && is_official_build && target_os != "ios"
 
-find_sdk_args = [ "--print_sdk_path" ]
+find_sdk_args = [
+  "--print_sdk_path",
+  "--print_bin_path",
+]
 if (!use_system_xcode) {
   find_sdk_args += [
     "--developer_dir",
@@ -66,10 +69,11 @@ if (_verify_sdk) {
 # second line.
 find_sdk_lines =
     exec_script("//build/mac/find_sdk.py", find_sdk_args, "list lines")
-mac_sdk_version = find_sdk_lines[1]
+mac_sdk_version = find_sdk_lines[2]
 if (mac_sdk_path == "") {
   mac_sdk_path = find_sdk_lines[0]
 }
+mac_bin_path = find_sdk_lines[1]
 
 script_name = "//build/config/mac/sdk_info.py"
 sdk_info_args = []

build/mac/find_sdk.py

@@ -4,11 +4,23 @@
 # found in the LICENSE file.
 
 """Prints the lowest locally available SDK version greater than or equal to a
-given minimum sdk version to standard output. If --developer_dir is passed, then
-the script will use the Xcode toolchain located at DEVELOPER_DIR.
+given minimum sdk version to standard output.
+
+If --developer_dir is passed, then the script will use the Xcode toolchain
+located at DEVELOPER_DIR.
+
+If --print_sdk_path is passed, then the script will also print the SDK path.
+If --print_bin_path is passed, then the script will also print the path to the
+toolchain bin dir.
 
 Usage:
-  python find_sdk.py [--developer_dir DEVELOPER_DIR] 10.6  # Ignores SDKs < 10.6
+  python find_sdk.py [--developer_dir DEVELOPER_DIR] [--print_sdk_path] \
+  [--print_bin_path] 10.6  # Ignores SDKs < 10.6
+
+Sample Output:
+/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
+/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/
+10.14
 """
 
 from __future__ import print_function
@@ -44,6 +56,9 @@ def main():
   parser.add_option("--print_sdk_path",
                     action="store_true", dest="print_sdk_path", default=False,
                     help="Additionally print the path the SDK (appears first).")
+  parser.add_option("--print_bin_path",
+                    action="store_true", dest="print_bin_path", default=False,
+                    help="Additionally print the path the toolchain bin dir.")
   parser.add_option("--developer_dir", help='Path to Xcode.')
   options, args = parser.parse_args()
   if len(args) != 1:
@@ -55,9 +70,7 @@ def main():
   # This is important to avoid since we want to minimize dependencies on the
   # xcode toolchain.
   if options.developer_dir:
-    sdk_dir = os.path.join(
-        options.developer_dir,
-        'Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs')
+    dev_dir = os.path.join(options.developer_dir, 'Contents/Developer')
   else:
     job = subprocess.Popen(['xcode-select', '-print-path'],
                            stdout=subprocess.PIPE,
@@ -67,8 +80,9 @@ def main():
       print(out, file=sys.stderr)
       print(err, file=sys.stderr)
       raise Exception('Error %d running xcode-select' % job.returncode)
-    sdk_dir = os.path.join(
-        out.rstrip(), 'Platforms/MacOSX.platform/Developer/SDKs')
+    dev_dir = out.rstrip()
+  sdk_dir = os.path.join(
+      dev_dir, 'Platforms/MacOSX.platform/Developer/SDKs')
 
   # Xcode must be installed, its license agreement must be accepted, and its
   # command-line tools must be installed. Stand-alone installations (in
@@ -104,6 +118,10 @@ def main():
     sdk_name = 'MacOSX' + best_sdk + '.sdk'
     print(os.path.join(sdk_dir, sdk_name))
 
+  if options.print_bin_path:
+    bin_path = 'Toolchains/XcodeDefault.xctoolchain/usr/bin/'
+    print(os.path.join(dev_dir, bin_path))
+
   return best_sdk