chromium: Disable jumbo builds

testing/chromium/build

@@ -53,7 +53,7 @@ set -- \
     use_glib=false \
     use_gnome_keyring=false \
     use_gold=false \
-    use_jumbo_build=true \
+    use_jumbo_build=false \
     use_kerberos=false \
     use_lld=false \
     use_official_google_api_keys=false \
@@ -68,6 +68,7 @@ for patch in *.patch; do
 done
 
 # Use 'clang' instead of 'gcc'.
+# Clang is the officially supported compiler and builds chromium faster.
 export CC=clang CXX=clang++ AR=llvm-ar NM=llvm-nm LD=clang++
 export PATH=$PWD/fix-python-bin:$PATH