Build libmonochrome.so with secondary toolchain

chrome/android/BUILD.gn

Index: chrome/android/BUILD.gn
diff --git a/chrome/android/BUILD.gn b/chrome/android/BUILD.gn
index 1e7eaa8f9a8f302df015238c7aff8a4750273853..28ce0d3d45a79ff05fafad19296ebcab07f36230 100644
--- a/chrome/android/BUILD.gn
+++ b/chrome/android/BUILD.gn
@@ -454,7 +454,12 @@ shared_library("chrome") {
 }
 
 # GYP: none
-if (!defined(webview_only_libmonochrome) || !webview_only_libmonochrome) {
+#
+# //chrome/android/monochrome is only needed in two cases

[agrieve, 2016/07/20 02:11:03]

nit: comment says what the if statement says, but doesn't answer the question of
why. It should say why it's needed in only these cases, and why it's worth
putting behind an if()

[michaelbai, 2016/07/20 16:51:11]

Refine the comment, hope it is clear now.

+# - build with 32-bit default_toolchain,
+# - or build with 32-bit android_secondary_abi_toolchain.
+if (!android_64bit_target_cpu ||
+    current_toolchain == android_secondary_abi_toolchain) {
   shared_library("monochrome") {
     sources = chrome_apk_gypi.monochrome_app_native_sources
     deps = [
@@ -469,6 +474,12 @@ if (!defined(webview_only_libmonochrome) || !webview_only_libmonochrome) {
 
     public_configs = extra_chrome_shared_library_configs
   }
+} else {
+  group("monochrome_secondary_abi_lib") {
+    public_deps = [
+      ":monochrome($android_secondary_abi_toolchain)",
+    ]
+  }
 }
 
 # GYP: //chrome/android/chrome_apk.gyp:libchrome_sync_shell