android: Turn on fission and symbol_level=2 by default.

build/config/compiler/compiler.gni

Index: build/config/compiler/compiler.gni
diff --git a/build/config/compiler/compiler.gni b/build/config/compiler/compiler.gni
index 73f3bf04e61c47a856a070d03479125e7508a212..ebb44deb53e01bd9c52f28c8d83fcc72f3eabdad 100644
--- a/build/config/compiler/compiler.gni
+++ b/build/config/compiler/compiler.gni
@@ -8,6 +8,7 @@ import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/pgo/pgo.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 import("//build_overrides/build.gni")
@@ -145,11 +146,6 @@ if (symbol_level == -1) {
     # With instrumentation enabled, debug info puts libchrome.so over 4gb, which
     # causes the linker to produce an invalid ELF. http://crbug.com/574476
     symbol_level = 0
-  } else if (is_android && !is_component_build &&
-             !(android_64bit_target_cpu && !build_apk_secondary_abi)) {
-    # Reduce symbol level when it will cause invalid elf files to be created
-    # (due to file size). https://crbug.com/648948.
-    symbol_level = 1
   } else if (is_win && use_goma && !is_clang) {
     # goma doesn't support PDB files, so we disable symbols during goma
     # compilation because otherwise the redundant debug information generated
@@ -179,8 +175,13 @@ if (symbol_level == -1) {
   }
 }
 
+if (use_debug_fission == "default") {
+  use_debug_fission =
+      symbol_level == 2 && !is_win && use_gold && cc_wrapper == ""
+}
+
 # Assert that the configuration isn't going to hit https://crbug.com/648948.
-assert(ignore_elf32_limitations || !is_android ||
+assert(ignore_elf32_limitations || !is_android || use_debug_fission ||
            (android_64bit_target_cpu && !build_apk_secondary_abi) ||
            is_component_build || symbol_level < 2,
        "Android 32-bit non-component builds cannot have symbol_level=2 " +