Version: Chromium master revision 9cedf753 (#418732)
OS: Windows 10 64-bit

What steps will reproduce the problem?
(1) Run chrome.exe with the --wait-for-debugger (or similar) command-line flag.

What is the expected output?
The embedded crashpad handler process (--type=crashpad-handler) should wait for the debugger to attach.

What do you see instead?
There is no way to wait for debugger attachment on crashpad handler process launch.

Please use labels and text to provide additional information.
The PlatformCrashpadInitialization() function in src/components/crash/content/app/crashpad_win.cc could check the current process command line for "wait-for-debugger" (or similar) and add it to |arguments| passed into StartHandler(). The crash_reporter::RunAsCrashpadHandler() function could then check for this flag and call base::debug::WaitForDebugger().