Switch ChromeOS Chromium login to use IJG libjpeg

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index be6e7797822f7fb52c246069e677a5113bcfdeb9..3b1433daa22856a59a8214c2511bf0aea7143e0d 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -881,11 +881,6 @@
           'use_canvas_skia%': 1,
         }],
 
-        ['chromeos==1', {
-          # When building for ChromeOS we dont want Chromium to use libjpeg_turbo.
-          'use_libjpeg_turbo%': 0,
-        }],
-
         ['OS=="android"', {
           # When building as part of the Android system, use system libraries
           # where possible to reduce ROM size.
@@ -1497,6 +1492,11 @@
     # ChromeVox, which can then be enabled via a command-line switch.
     'use_chromevox_next%': 0,
 
+    # Used to set libjpeg_gyp_path. Chrome OS ui/gfx/gfx.gyp uses the IJG path
+    # for robust login screen decoding.
+    'libjpeg_ijg_gyp_path': '../third_party/libjpeg/libjpeg.gyp',
+    'libjpeg_turbo_gyp_path': '../third_party/libjpeg_turbo/libjpeg.gyp',
+
     'conditions': [
       # The version of clang shipped upstream does not find C++ headers when
       # using -stdlib=libc++ so we instead need to use the version of clang
@@ -1985,9 +1985,9 @@
       # library used by Chromium.
       ['use_system_libjpeg==1 or use_libjpeg_turbo==0', {
         # Configuration for using the system libjeg is here.
-        'libjpeg_gyp_path': '../third_party/libjpeg/libjpeg.gyp',
+        'libjpeg_gyp_path': '<(libjpeg_ijg_gyp_path)',
       }, {
-        'libjpeg_gyp_path': '../third_party/libjpeg_turbo/libjpeg.gyp',
+        'libjpeg_gyp_path': '<(libjpeg_turbo_gyp_path)',
       }],
 
       # Options controlling the use of GConf (the classic GNOME configuration