[Android] Enable multidex for debug builds of ChromePublic.

build/android/main_dex_action.gypi

Index: build/android/main_dex_action.gypi
diff --git a/build/android/main_dex_action.gypi b/build/android/main_dex_action.gypi
index 06717ddcff61033f445597296aca597126ba2f36..7316ae20e9da08ba3025a693ffcb766e70e212b0 100644
--- a/build/android/main_dex_action.gypi
+++ b/build/android/main_dex_action.gypi
@@ -21,7 +21,7 @@
 {
   'message': 'Generating main dex classes list for <(jar_path)',
   'variables': {
-    'jar_path%': '',
+    'jar_paths%': [],
     'output_path%': '',
     'main_dex_list_script': '<(DEPTH)/build/android/gyp/main_dex_list.py',
     'main_dex_rules_path': '<(DEPTH)/build/android/main_dex_classes.flags',
@@ -30,6 +30,7 @@
     '<(jar_path)',
     '<(main_dex_list_script)',
     '<(main_dex_rules_path)',
+    '<(multidex_configuration_path)',
   ],
   'outputs': [
     '<(output_path)',
@@ -39,6 +40,7 @@
     '--main-dex-list-path', '<(output_path)',
     '--android-sdk-tools', '<(android_sdk_tools)',
     '--main-dex-rules-path', '<(main_dex_rules_path)',
-    '<(jar_path)',
+    '--multidex-configuration-path', '<(multidex_configuration_path)',
+    '<@(jar_paths)',
   ]
 }