Add MODIFY_AUDIO_SETTINGS permission in Android manifest and implementation in audio manager.

media/media.gyp

Index: media/media.gyp
===================================================================
--- media/media.gyp	(revision 187192)
+++ media/media.gyp	(working copy)
@@ -553,6 +553,7 @@
             '<(SHARED_INTERMEDIATE_DIR)/media',
           ],
           'dependencies': [
+            'audio_manager_android_jni_headers',
             'video_capture_android_jni_headers',
           ],
         }],
@@ -1436,6 +1437,17 @@
           'includes': [ '../build/jar_file_jni_generator.gypi' ],
         },
         {
+          'target_name': 'audio_manager_android_jni_headers',
+          'type': 'none',
+          'sources': [
+            'base/android/java/src/org/chromium/media/AudioManagerAndroid.java',
+          ],
+          'variables': {
+            'jni_gen_package': 'media',
+          },
+          'includes': [ '../build/jni_generator.gypi' ],
+        },
+        {
           'target_name': 'video_capture_android_jni_headers',
           'type': 'none',
           'dependencies': [