Revert of Switch Android Builder on chromium.webkit to gn.

tools/mb/mb_config.pyl

Index: tools/mb/mb_config.pyl
diff --git a/tools/mb/mb_config.pyl b/tools/mb/mb_config.pyl
index 9968a2dc0fa7e5268314248ac34f7a7235b1e725..8888e0cc3e0f69023d5d26c336ecb2b8c62690e2 100644
--- a/tools/mb/mb_config.pyl
+++ b/tools/mb/mb_config.pyl
@@ -513,8 +513,8 @@
     },
 
     'chromium.webkit': {
-      'Android Builder': 'android_gn_release_bot_minimal_symbols',
-      'WebKit Android (Nexus4)': 'none',
+      'Android Builder': 'gyp_release_bot_android',
+      'WebKit Android (Nexus4)': 'gyp_release_bot_android',
       'WebKit Linux (dbg)': 'swarming_gn_debug_bot_x64',
       'WebKit Linux ASAN': 'swarming_gn_asan_lsan_release_bot_x64',
       'WebKit Linux Leak': 'swarming_gn_release_bot_x64',
@@ -1302,6 +1302,10 @@
       'gyp', 'release_bot',
     ],
 
+    'gyp_release_bot_android': [
+      'gyp', 'release_bot', 'android',
+    ],
+
     'gyp_release_bot_x86': [
       'gyp', 'release_bot', 'x86',
     ],