Use thumb versions of external libraries with ARMv7.

build/config/android/config.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This file contains common system config stuff for the Android build.
 
 if (is_android) {
   has_chrome_android_internal = exec_script("//build/dir_exists.py",
           [ rebase_path("//clank", root_build_dir) ],
           "string") == "True"
@@ skipping 19 matching lines @@
     android_default_keystore_path = "//build/android/ant/chromium-debug.keystore"
     android_default_keystore_name = "chromiumdebugkey"
     android_default_keystore_password = "chromium"
 
     # This is a unique identifier for a given build. It's used for
     # identifying various build artifacts corresponding to a particular build of
     # chrome (e.g. where to find archived symbols).
     android_chrome_build_id = "\"\""
   }
 
+  # ABI ------------------------------------------------------------------------
+
+  if (cpu_arch == "x86") {
+    android_app_abi = "x86"
+  } else if (cpu_arch == "arm") {
+    import("//build/config/arm.gni")
+    if (arm_version < 7) {
+      android_app_abi = "armeabi"
+    } else {
+      android_app_abi = "armeabi-v7a"
+    }
+  } else if (cpu_arch == "mipsel") {
+    android_app_abi = "mips"
+  } else {
+    assert(false, "Unknown Android ABI: " + cpu_arch)
+  }
+
   # Host stuff -----------------------------------------------------------------
 
   # Defines the name the Android build gives to the current host CPU
   # architecture, which is different than the names GN uses.
   if (build_cpu_arch == "x64") {
     android_host_arch = "x86_64"
   } else if (build_cpu_arch == "x86") {
     android_host_arch = "x86"
   } else {
     assert(false, "Need Android toolchain support for your build CPU arch.")
@@ skipping 49 matching lines @@
   if (cpu_arch == "x86") {
     android_prebuilt_arch = "android-x86"
     _binary_prefix = "i686-linux-android"
     android_toolchain_root = "$x86_android_toolchain_root"
     android_libgcc_file =
       "$android_toolchain_root/lib/gcc/i686-linux-android/${_android_toolchain_version}/libgcc.a"
   } else if (cpu_arch == "arm") {
     android_prebuilt_arch = "android-arm"
     _binary_prefix = "arm-linux-androideabi"
     android_toolchain_root = "$arm_android_toolchain_root"
-    android_libgcc_file =
-      "$android_toolchain_root/lib/gcc/arm-linux-androideabi/${_android_toolchain_version}/libgcc.a"
+    if (arm_use_thumb) {
+      android_libgcc_file =
+        "$android_toolchain_root/lib/gcc/arm-linux-androideabi/${_android_toolchain_version}/thumb/libgcc.a"
+    } else {
+      android_libgcc_file =
+        "$android_toolchain_root/lib/gcc/arm-linux-androideabi/${_android_toolchain_version}/libgcc.a"
+    }
   } else if (cpu_arch == "mipsel") {
     android_prebuilt_arch = "android-mips"
     _binary_prefix = "mipsel-linux-android"
     android_toolchain_root = "$mips_android_toolchain_root"
     android_libgcc_file =
       "$android_toolchain_root/lib/gcc/mipsel-linux-android/${_android_toolchain_version}/libgcc.a"
   } else {
     assert(false, "Need android libgcc support for your target arch.")
   }
 
   android_tool_prefix = "$android_toolchain_root/bin/$_binary_prefix-"
   android_readelf = "${android_tool_prefix}readelf"
   android_objcopy = "${android_tool_prefix}objcopy"
   android_gdbserver = "$android_ndk_root/prebuilt/$android_prebuilt_arch/gdbserver/gdbserver"
 
   # stlport stuff --------------------------------------------------------------
 
   if (component_mode == "shared_library") {
     android_stlport_library = "stlport_shared"
   } else {
     android_stlport_library = "stlport_static"
   }
-
-  # ABI ------------------------------------------------------------------------
-
-  if (cpu_arch == "x86") {
-    android_app_abi = "x86"
-  } else if (cpu_arch == "arm") {
-    import("//build/config/arm.gni")
-    if (arm_version < 7) {
-      android_app_abi = "armeabi"
-    } else {
-      android_app_abi = "armeabi-v7a"
-    }
-  } else if (cpu_arch == "mipsel") {
-    android_app_abi = "mips"
-  } else {
-    assert(false, "Unknown Android ABI: " + cpu_arch)
-  }
 } else {
   if (!defined(is_android_webview_build)) {
     is_android_webview_build = false
   }
 }