Add templates for building java and running the jni_generator.

base/base.gyp

Index: base/base.gyp
diff --git a/base/base.gyp b/base/base.gyp
index c551ec759106d5c9b7bd97e1113e2466e8657af2..25b8122ff61709ff7c5ff662c3e37b65b7ddd993 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -117,29 +117,28 @@
     {
       'target_name': 'base_jni_headers',
       'type': 'none',
-      'actions': [
-        {
-          'action_name': 'generate_jni_headers',
-          'inputs': [
-            'android/jni_generator/jni_generator.py',
-            'android/java/org/chromium/base/BuildInfo.java',
-            'android/java/org/chromium/base/PathUtils.java',
-            'android/java/org/chromium/base/SystemMessageHandler.java',
-          ],
-          'outputs': [
-            '<(SHARED_INTERMEDIATE_DIR)/base/jni/build_info_jni.h',
-            '<(SHARED_INTERMEDIATE_DIR)/base/jni/path_utils_jni.h',
-            '<(SHARED_INTERMEDIATE_DIR)/base/jni/system_message_handler_jni.h',
-          ],
-          'action': [
-            'python',
-            'android/jni_generator/jni_generator.py',
-            '-o',
-            '<@(_inputs)',
-            '<@(_outputs)',
-          ],
-        }
-      ],
+      'variables': {
+        'java_sources': [
+          'android/java/org/chromium/base/BuildInfo.java',
+          'android/java/org/chromium/base/PathUtils.java',
+          'android/java/org/chromium/base/SystemMessageHandler.java',
+        ],
+        'jni_headers': [
+          '<(SHARED_INTERMEDIATE_DIR)/base/jni/build_info_jni.h',
+          '<(SHARED_INTERMEDIATE_DIR)/base/jni/path_utils_jni.h',
+          '<(SHARED_INTERMEDIATE_DIR)/base/jni/system_message_handler_jni.h',
+        ],
+      },
+      'includes': [ '../build/jni_generator.gypi' ],
+    },
+    {
+      'target_name': 'base_java',
+      'type': 'none',
+      'variables': {
+        'package_name': 'base',
+        'java_in_dir': 'android/java',
+      },
+      'includes': [ '../build/java.gypi' ],
     },
     # Include this target for a main() function that simply instantiates
     # and runs a base::TestSuite.