tools: Add VSCode setup (fixes #3906)

Add tooling to set up a Visual Studio Code development environment
for CEF. See script output for usage.

Run: python3 tools/setup_vscode.py

tools/gclient_hook.py

@@ -10,6 +10,7 @@ from gclient_util import *
 from gn_args import GetAllPlatformConfigs, GetConfigFileContents
 import issue_1999
 import os
+from setup_vscode import GetPreferredOutputDirectory, UpdateCompileCommandsJSON
 import sys
 
 # The CEF directory is the parent directory of _this_ script.
@@ -26,7 +27,7 @@ elif sys.platform.startswith('linux'):
   platform = 'linux'
 else:
   print('Unknown operating system platform')
-  sys.exit()
+  sys.exit(1)
 
 print("\nGenerating CEF translated files...")
 cmd = [sys.executable, 'tools/version_manager.py', '-u', '--fast-check']
@@ -134,6 +135,10 @@ if platform == 'windows':
     gn_args['windows_sdk_version'] = os.environ['SDK_VERSION']
 
 configs = GetAllPlatformConfigs(gn_args)
+
+# Returns the preferred output directory for VSCode, or None.
+preferred_dir = GetPreferredOutputDirectory(configs.keys())
+
 for dir, config in configs.items():
   # Create out directories and write the args.gn file.
   out_path = os.path.join(src_dir, 'out', dir)
@@ -149,3 +154,7 @@ for dir, config in configs.items():
   RunAction(src_dir, cmd)
   if platform == 'windows':
     issue_1999.apply(out_path)
+
+  if dir == preferred_dir and not UpdateCompileCommandsJSON(
+      src_dir, out_path, create=False):
+    sys.exit(1)