Move gvr library proguard config to chrome_public_apk_tmpl.gni so that Chrome apk can also use it

chrome/android/chrome_public_apk_tmpl.gni

 # Copyright 2015 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.
 
 import("//base/android/linker/config.gni")
 import("//build/config/android/rules.gni")
 import("//chrome/common/features.gni")
 import("//third_party/leakcanary/config.gni")
 import("channel.gni")
 
@@ skipping 36 matching lines @@
       _prev_proguard_configs = []
       if (defined(proguard_configs)) {
         _prev_proguard_configs = proguard_configs
       }
       proguard_configs = []
       proguard_configs = _prev_proguard_configs + [
                            "//chrome/android/java/proguard.flags",
                            "//base/android/base_proguard_config.flags",
                            "//base/android/release_proguard_config.flags",
                          ]
+      if (enable_webvr) {
+        proguard_configs +=
+            [ "//third_party/gvr-android-sdk/proguard/base.flags" ]
+      }
     }
 
     if (!defined(use_chromium_linker)) {
       use_chromium_linker = chrome_public_apk_use_chromium_linker
     }
 
     if (use_chromium_linker) {
       if (!defined(load_library_from_apk)) {
         load_library_from_apk = chrome_public_apk_load_library_from_apk
       }
 
       if (!defined(enable_relocation_packing)) {
         enable_relocation_packing = chrome_public_apk_use_relocation_packer
       }
     }
   }
 }