[Android] Enable multidex for debug builds of ChromePublic.

build/android/java_cpp_template.gypi

Index: build/android/java_cpp_template.gypi
diff --git a/build/android/java_cpp_template.gypi b/build/android/java_cpp_template.gypi
index 3296659240b57b7f2711ac7d204622988b7de0c7..f4ea0a9195d38eaa940040c46ada3e6f1e8fbaa6 100644
--- a/build/android/java_cpp_template.gypi
+++ b/build/android/java_cpp_template.gypi
@@ -34,6 +34,7 @@
 {
   # Location where all generated Java sources will be placed.
   'variables': {
+    'additional_gcc_preprocess_options': [],
     'include_path%': '<(DEPTH)',
     'output_dir': '<(SHARED_INTERMEDIATE_DIR)/templates/<(_target_name)/<(package_name)',
   },
@@ -74,6 +75,7 @@
         '--include-path=<(include_path)',
         '--output=<(output_path)',
         '--template=<(RULE_INPUT_PATH)',
+        '<@(additional_gcc_preprocess_options)',
       ],
       'message': 'Generating Java from cpp template <(RULE_INPUT_PATH)',
     }