chromium: Update all channels to latest versions.

With this commit, the following new upstream versions are introduced:

stable: 38.0.2125.101 -> 39.0.2171.65
beta:   39.0.2171.19  -> 40.0.2214.10
dev:    40.0.2182.3   -> 41.0.2224.3

We can now remove missing_alg_import.patch, because version 39 is nom
stable and thus fixes the missing include directive upstream.

However, starting with version 40, we hit a few bugs with system
protobuf, so we're disabling it for every version >=40 to avoid
runtime/startup errors.

Here is the stable channel announcement for version 39 on the official
blog:

http://googlechromereleases.blogspot.de/2014/11/stable-channel-update_18.html

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
chromium: Allow env vars for passing plugin paths.

Introduces environment variables to set plugin base paths. The schema
for these is like NIX_CHROMIUM_PLUGIN_PATH_<N>. Where <N> is the path
type we want to change, the supported (full) variable names are:

 * NIX_CHROMIUM_PLUGIN_PATH_ALL
 * NIX_CHROMIUM_PLUGIN_PATH_PEPPERFLASH
 * NIX_CHROMIUM_PLUGIN_PATH_FILEFLASH
 * NIX_CHROMIUM_PLUGIN_PATH_PDF
 * NIX_CHROMIUM_PLUGIN_PATH_FILE_EFFECTS
 * NIX_CHROMIUM_PLUGIN_PATH_NACL
 * NIX_CHROMIUM_PLUGIN_PATH_PNACL
 * NIX_CHROMIUM_PLUGIN_PATH_WIDEVINE

Whereas NIX_CHROMIUM_PLUGIN_PATH_ALL is the plugin base path for every
path which is not set explicitly, so by setting ..._ALL and not setting
..._WIDEVINE, the widevine plugin will be searched in the directory
specified using ..._ALL.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
cups: bump 1.5.4 -> 1.7.5
chromium: Switch to use open-source PDF plugin.

The Chromium PDF plugin is now available as open source software and is
already included in the Chromium source tree in current stable, so there
is no need to extract it from the Chrome binary package anymore.

See release announcement at http://blog.foxitsoftware.com/?p=641

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
hydra pickup...

Signed-off-by: aszlig <aszlig@redmoonstudios.org>