WiX custom action for installing a Firefox extension with enterprise policy

FirefoxAction is a custom action for WiX that installs the given Firefox extension with the Firefox enterprise policy engine.

The custom action should be added to a WiX project as follows, it must be deferred and not use impersonation (i.e. run in privileged mode for registry access):

<Binary Id="FirefoxAction.CA.dll" SourceFile="$(sys.SOURCEFILEDIR)FirefoxAction.CA.dll" />
<CustomAction Id="ExtensionSettingsInstall" Return="check" Execute="deferred" Impersonate="no"
  BinaryKey="FirefoxAction.CA.dll" DllEntry="ExtensionSettingsInstall" />
<CustomAction Id="ExtensionSettingsRemove" Return="check" Execute="deferred" Impersonate="no"
  BinaryKey="FirefoxAction.CA.dll" DllEntry="ExtensionSettingsRemove" />

The Firefox extension UUID and AMO URL must be passed in via CustomSettingsData properties via dedicated custom actions as follows:

<CustomAction Id="SetExtensionSettingsForInstall" Property="ExtensionSettingsInstall"
  Value="EXTENSIONSETTINGS_UUID=$(var.FIREFOX_UUID);EXTENSIONSETTINGS_URL=$(var.FIREFOX_URL)" />
<CustomAction Id="SetExtensionSettingsForRemove" Property="ExtensionSettingsRemove"
  Value="EXTENSIONSETTINGS_UUID=$(var.FIREFOX_UUID);EXTENSIONSETTINGS_URL=$(var.FIREFOX_URL)" />

The custom actions must be scheduled in InstallExecuteSequence as follows:

<InstallExecuteSequence>
  <Custom Action="SetExtensionSettingsForInstall" Before="InstallInitialize" />
  <Custom Action="ExtensionSettingsInstall" Before="InstallFinalize">
    NOT REMOVE="ALL"
  </Custom>
  <Custom Action="SetExtensionSettingsForRemove" Before="InstallInitialize" />
  <Custom Action="ExtensionSettingsRemove" Before="InstallFinalize">
    REMOVE="ALL" AND NOT UPGRADINGPRODUCTCODE
  </Custom>
</InstallExecuteSequence>

The code has been forked from the OpenEID Windows installer project.