[Android] Add gyp support for multidex.

build/java.gypi

Index: build/java.gypi
diff --git a/build/java.gypi b/build/java.gypi
index 73c550de071e310fadb3a04d871497b1d01e6269..3e3db1246ff63609b3da93c2fdc118a08e22f63f 100644
--- a/build/java.gypi
+++ b/build/java.gypi
@@ -64,6 +64,7 @@
     'instr_stamp': '<(intermediate_dir)/instr.stamp',
     'additional_input_paths': [],
     'dex_path': '<(PRODUCT_DIR)/lib.java/<(_target_name).dex.jar',
+    'main_dex_list_path': '<(intermediate_dir)/main_dex_list.txt',
     'generated_src_dirs': ['>@(generated_R_dirs)'],
     'generated_R_dirs': [],
     'has_java_resources%': 0,
@@ -113,6 +114,7 @@
         'variables': {
           'input_jars_paths': ['<(jar_final_path)'],
           'library_dexed_jars_paths': ['<(dex_path)'],
+          'main_dex_list_paths': ['<(main_dex_list_path)'],
         },
       },
     }],
@@ -297,6 +299,14 @@
       ]
     },
     {
+      'action_name': 'main_dex_list_for_<(_target_name)',
+      'variables': {
+        'jar_path': '<(javac_jar_path)',
+        'output_path': '<(main_dex_list_path)',
+      },
+      'includes': [ 'android/main_dex_action.gypi' ],
+    },
+    {
       'action_name': 'instr_jar_<(_target_name)',
       'message': 'Instrumenting <(_target_name) jar',
       'variables': {