[Cronet] Enforce ARMv7 Cronet doesn't inadvertently use ARM Neon instructions

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 0915f917256f3721bf7284762ea88f46144e8966..557dc00c7f2dad29456a1554c5211f8c5e877f70 100644
--- a/tools/mb/mb_config.pyl
+++ b/tools/mb/mb_config.pyl
@@ -1049,11 +1049,11 @@
 
     'android_cronet_data_reduction_proxy_gn_release_bot_minimal_symbols': [
       'android', 'cronet', 'data_reduction_proxy', 'gn',
-      'release_bot_minimal_symbols', 'arm'
+      'release_bot_minimal_symbols', 'arm_no_neon'
     ],
 
     'android_cronet_gn_debug_static_bot': [
-      'android', 'cronet', 'gn', 'debug_static_bot', 'arm'
+      'android', 'cronet', 'gn', 'debug_static_bot', 'arm_no_neon'
     ],
 
     'android_cronet_gn_debug_static_bot_arm64': [
@@ -1065,7 +1065,7 @@
     ],
 
     'android_cronet_gn_release_bot_minimal_symbols': [
-      'android', 'cronet', 'gn', 'release_bot_minimal_symbols', 'arm'
+      'android', 'cronet', 'gn', 'release_bot_minimal_symbols', 'arm_no_neon'
     ],
 
     'android_cronet_gn_release_bot_minimal_symbols_arm64': [
@@ -1077,8 +1077,8 @@
     ],
 
     'android_cronet_gn_release_bot_minimal_symbols_clang_asan': [
-      'android', 'cronet', 'gn', 'release_bot_minimal_symbols', 'arm', 'clang',
-      'asan'
+      'android', 'cronet', 'gn', 'release_bot_minimal_symbols', 'arm_no_neon',
+      'clang', 'asan'
     ],
 
     'android_cronet_gn_release_bot_minimal_symbols_mipsel': [
@@ -2025,6 +2025,12 @@
       'gyp_defines': 'target_arch=arm',
     },
 
+    'arm_no_neon': {
+      'mixins': ['arm'],
+      'gn_args': 'arm_use_neon=false',
+      'gyp_defines': 'arm_neon=0',
+    },
+
     'arm64': {
       'gn_args': 'target_cpu="arm64"',
       'gyp_defines': 'target_arch=arm64',