[Android] Add gyp support for multidex.

build/config/android/rules.gni

Index: build/config/android/rules.gni
diff --git a/build/config/android/rules.gni b/build/config/android/rules.gni
index f627e43699ec53c375921868f619e07dd789f2cf..9fa1f80b4c8bd6ef74be9bbc0848908231daddf3 100644
--- a/build/config/android/rules.gni
+++ b/build/config/android/rules.gni
@@ -1085,6 +1085,9 @@ template("java_library") {
 #   proguard_preprocess: If true, proguard preprocessing will be run. This can
 #     be used to remove unwanted parts of the library.
 #   proguard_config: Path to the proguard config for preprocessing.
+#   supports_android: If true, Android targets (android_library, android_apk)

[Yaron, 2015/08/24 15:28:44]

Am I missing something? I don't see where this is enforced. Also, wouldn't this
be the default? We have few targets which don't work on android.

[jbudorick, 2015/08/24 21:13:51]

requires_android and supports_android are enforced here:
https://code.google.com/p/chromium/codesearch#chromium/src/build/android/gyp/...

Neither is enabled by default for java_X, but they are for android_X.

+#     may depend on this target. Note: if true, this target must only use the
+#     subset of Java available on Android.
 #
 # Example
 #   java_prebuilt("foo_java") {
@@ -1116,6 +1119,9 @@ template("java_prebuilt") {
     if (defined(invoker.proguard_preprocess)) {
       proguard_preprocess = invoker.proguard_preprocess
     }
+    if (defined(invoker.supports_android)) {
+      supports_android = invoker.supports_android
+    }
   }
 }