GN(android): Default libs logic from runtime_library -> default_libs

build/config/android/BUILD.gn

Index: build/config/android/BUILD.gn
diff --git a/build/config/android/BUILD.gn b/build/config/android/BUILD.gn
index 2d9d677529fd57f994c47c656f27671d901948eb..031a72be210ebaa89298b581115cf82a84f679c1 100644
--- a/build/config/android/BUILD.gn
+++ b/build/config/android/BUILD.gn
@@ -142,40 +142,6 @@ config("runtime_library") {
   ]
 
   defines = [ "__GNU_SOURCE=1" ]  # Necessary for clone().
-  ldflags = [ "-nostdlib" ]
-  lib_dirs = [ "$android_libcpp_root/libs/$android_app_abi" ]
-
-  # The libc++ runtime library (must come first).
-  # ASan needs to dynamically link to libc++ even in static builds so
-  # that it can interpose operator new.
-  if (is_component_build || is_asan) {
-    libs = [ "c++_shared" ]
-  } else {
-    libs = [ "c++_static" ]
-  }
-
-  # libgcc must come before libdl for ld.bfd (MIPS)
-  if (current_cpu == "mipsel") {
-    libs += [
-      # ld linker is used for mips Android, and ld does not accept library
-      # absolute path prefixed by "-l"; Since libgcc does not exist in mips
-      # sysroot the proper library will be linked.
-      # TODO(gordanac): Remove once gold linker is used for mips Android.
-      "gcc",
-    ]
-  } else {
-    libs += [
-      # Manually link the libgcc.a that the cross compiler uses. This is
-      # absolute because the linker will look inside the sysroot if it's not.
-      rebase_path(android_libgcc_file),
-    ]
-  }
-
-  libs += [
-    "c",
-    "dl",
-    "m",
-  ]
 
   if (is_clang) {
     # Work around incompatibilities between bionic and clang headers.
@@ -188,12 +154,7 @@ config("runtime_library") {
   # TODO(jdduke) Re-enable on mips after resolving linking
   # issues with libc++ (crbug.com/456380).
   if (current_cpu != "mipsel" && current_cpu != "mips64el") {
-    ldflags += [ "-Wl,--warn-shared-textrel" ]
-  }
-
-  # Clang with libc++ does not require an explicit atomic library reference.
-  if (!is_clang) {
-    libs += [ "atomic" ]
+    ldflags = [ "-Wl,--warn-shared-textrel" ]
   }
 }