In so doing, this CL also contains:

- Change BrowserDistribution::GetShortcutName to use the localized name
  for Chromium rather than a hardcoded string.
- Delete GoogleChromeDistribution::GetShortcutName since the override is
  no longer needed.
- Consistently apply DCHECK_EQ to all public ShellUtil functions that
  take a BrowserDistribution*, and remove such checks from internal
  functions.
- Remove the BrowserDistribution parameter from:
  - ShellUtil::GetCurrentInstallationSuffix
  - ShellUtil::QuickIsChromeRegisteredInHKLM
- Generally reduce the use of BrowserDistribution within ShellUtil where
  sensible.
- Make GetApplicationName an implementation detail of ShellUtil.

This is another step in bringing brand-specific constants together into
one place, eventually leading to the demise of BrowserDistribution.

BUG=373987

Review-Url: https://codereview.chromium.org/2778223004
Cr-Commit-Position: refs/heads/master@{#460813}