Convert Chromium reports to puppeteer (#21788)

Update Chromium to a recent version compatible with Puppeteer.

Update Chromium build scripts to initialize build environments and work with
recent versions of Chromium.

Modify Chromium reporting logic to be driven mostly by Puppeteer.

x-pack/build_chromium/init.py

@@ -0,0 +1,32 @@
+import os, platform
+from build_util import runcmd, mkdir, md5_file, root_dir, configure_environment
+
+# This is a cross-platform initialization script which should only be run
+# once per environment, and isn't intended to be run directly. You should
+# run the appropriate platform init script (e.g. Linux/init.sh) which will
+# call this once the platform-specific initialization has completed.
+
+os.chdir(root_dir)
+
+# Configure git
+runcmd('git config --global core.autocrlf false')
+runcmd('git config --global core.filemode false')
+runcmd('git config --global branch.autosetuprebase always')
+
+# Grab Chromium's custom build tools, if they aren't already installed
+# (On Windows, they are installed before this Python script is run)
+if not os.path.isdir('depot_tools'):
+  runcmd('git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git')
+
+# Put depot_tools on the path so we can properly run the fetch command
+configure_environment()
+
+# Fetch the Chromium source code
+mkdir('chromium')
+os.chdir('chromium')
+runcmd('fetch chromium')
+
+# Build Linux deps
+if platform.system() == 'Linux':
+  os.chdir('src')
+  runcmd('build/install-build-deps.sh')