Clean up gyp settings for libjpeg

The gyp settings for libjpeg currently have a number of problems ...
- Settings for using the system libjpeg are replicated in the gyp files for both libjpeg and libjpeg_turbo.
- The default setting for use_system_libjpeg is different depending on whether libjpeg or libjpeg_turbo is in use. This is unintuitive, as libjpeg_turbo is a drop-in replacement for libjpeg.

This patch improves the situation ...
- Improve documentation about the interaction between use_system_libjpeg and use_libjpeg_turbo.
- Use the libjpeg gyp file whenever use_system_libjpeg==1. This means that the settings for using the system libjpeg are only needed here. (A later patch will remove them from libjpeg_turbo's gyp file). It also means that the libjpeg_turbo repository can be excluded when use_system_libjpeg==1.
- Move all settings concerned with use_system_libjpeg to the libjpeg gyp file.

Note that with this change, we lose the OS-specific defaults for use_system_libjpeg when use_libjpeg_turbo==0. These defaults are currently not used, as use_libjpeg_turbo==1 always.

Review URL: https://chromiumcodereview.appspot.com/10696082

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@147254 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 9 insertions, 17 deletions

diff --git a/third_party/iccjpeg/iccjpeg.gyp b/third_party/iccjpeg/iccjpeg.gyp
index 25d25ed..7801148 100644
--- a/third_party/iccjpeg/iccjpeg.gyp
+++ b/third_party/iccjpeg/iccjpeg.gyp
@@ -14,13 +14,6 @@
         'iccjpeg.c',
         'iccjpeg.h',
       ],
-      'conditions': [
-        ['os_bsd==1 and use_system_libjpeg==1', {
-          'include_dirs': [
-            '/usr/local/include',
-          ],
-        }],
-      ],
       'direct_dependent_settings': {
         'include_dirs': [
           '.',
diff --git a/third_party/libjpeg/libjpeg.gyp b/third_party/libjpeg/libjpeg.gyp
index 12cc882..8f0dac8 100644
--- a/third_party/libjpeg/libjpeg.gyp
+++ b/third_party/libjpeg/libjpeg.gyp
@@ -3,16 +3,8 @@
 # found in the LICENSE file.
 
 {
-  'variables': {
-    'conditions': [
-      [ 'os_posix == 1 and OS != "mac"', {
-        # Link to system .so since we already use it due to GTK.
-        'use_system_libjpeg%': 1,
-      }, {  # os_posix != 1 or OS == "mac"
-        'use_system_libjpeg%': 0,
-      }],
-    ],
-  },
+  # This file handles building both with our local libjpeg and with the system
+  # libjpeg.
   'conditions': [
     ['use_system_libjpeg==0', {
       'targets': [
@@ -94,6 +86,13 @@
             'defines': [
               'USE_SYSTEM_LIBJPEG',
             ],
+            'conditions': [
+              ['os_bsd==1', {
+                'include_dirs': [
+                  '/usr/local/include',
+                ],
+              }],
+            ],
           },
           'link_settings': {
             'libraries': [