Disable libyuv jpeg support on Android

MJPEG capture is not used on Android. Therefore, disable jpeg support to
reduce libjingle_peerconnection_so file size by removing dependency to
libjpeg_turbo.

Also, remove unused build_libjpeg and rtc_build_libjpeg variables.

Review-Url: https://codereview.webrtc.org/1978243002
Cr-Commit-Position: refs/heads/master@{#12777}

webrtc/build/common.gypi

@@ -114,7 +114,6 @@
     # Disable these to not build components which can be externally provided.
     'build_expat%': 1,
     'build_json%': 1,
-    'build_libjpeg%': 1,
     'build_libsrtp%': 1,
     'build_libvpx%': 1,
     'libvpx_build_vp9%': 1,
@@ -219,9 +218,6 @@
         'include_tests%': 1,
         'restrict_webrtc_logging%': 0,
       }],
-      ['OS=="ios"', {
-        'build_libjpeg%': 0,
-      }],
       ['target_arch=="arm" or target_arch=="arm64" or target_arch=="mipsel"', {
         'prefer_fixed_point%': 1,
       }],

webrtc/build/webrtc.gni

@@ -36,7 +36,6 @@ declare_args() {
   # Disable these to not build components which can be externally provided.
   rtc_build_expat = true
   rtc_build_json = true
-  rtc_build_libjpeg = true
   rtc_build_libvpx = true
   rtc_build_libyuv = true
   rtc_build_openmax_dl = true
@@ -69,7 +68,6 @@ declare_args() {
   }
 
   if (is_ios) {
-    rtc_build_libjpeg = false
     rtc_enable_protobuf = false
   }
 

webrtc/supplement.gypi

@@ -24,6 +24,11 @@
           }],
         ],
       }],
+      ['OS=="android"', {
+        # MJPEG capture is not used on Android. Disable to reduce
+        # libjingle_peerconnection_so file size.
+        'libyuv_disable_jpeg%': 1,
+      }],
     ],
   },
   'target_defaults': {