content: add header files of public that were not listed in the BUILD.gn file

content/browser/BUILD.gn

 # Copyright 2014 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("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//gpu/vulkan/features.gni")
 import("//media/media_options.gni")
 import("//ppapi/features/features.gni")
 import("//printing/features/features.gni")
@@ skipping 198 matching lines @@
     "$target_gen_dir/devtools/protocol/target.cc",
     "$target_gen_dir/devtools/protocol/target.h",
     "$target_gen_dir/devtools/protocol/tethering.cc",
     "$target_gen_dir/devtools/protocol/tethering.h",
     "$target_gen_dir/devtools/protocol/tracing.cc",
     "$target_gen_dir/devtools/protocol/tracing.h",
     "../common/service_manager/child_connection.cc",
     "../common/service_manager/child_connection.h",
     "../zygote/zygote_linux.cc",
     "../zygote/zygote_linux.h",
+    "../zygote/zygote_main.h",
     "../zygote/zygote_main_linux.cc",
     "accessibility/accessibility_tree_formatter.cc",
     "accessibility/accessibility_tree_formatter.h",
     "accessibility/accessibility_tree_formatter_blink.cc",
     "accessibility/accessibility_tree_formatter_blink.h",
     "accessibility/accessibility_tree_formatter_mac.mm",
     "accessibility/accessibility_tree_formatter_stub.cc",
     "accessibility/accessibility_tree_formatter_utils_win.cc",
     "accessibility/accessibility_tree_formatter_utils_win.h",
     "accessibility/accessibility_tree_formatter_win.cc",
@@ skipping 1899 matching lines @@
   if (!is_component_build) {
     public_deps = [
       ":browser",
     ]
   } else {
     public_deps = [
       "//third_party/leveldatabase",
     ]
   }
 }