Adding option for Proguard jar to be switched.

base/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 2353 matching lines @@
       "memory/memory_pressure_listener.h",
     ]
   }
 
   # GYP: //base/base.gyp:base_build_config_gen
   java_cpp_template("base_build_config_gen") {
     sources = [
       "android/java/templates/BuildConfig.template",
     ]
     package_name = "org/chromium/base"
+
+    defines = []
+    if (!is_java_debug) {
+      defines += [ "NDEBUG" ]
+    }
   }
 
   # GYP: //base/base.gyp:base_native_libraries_gen
   java_cpp_template("base_native_libraries_gen") {
     sources = [
       "android/java/templates/NativeLibraries.template",
     ]
     package_name = "org/chromium/base/library_loader"
   }
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }