Only generate suggested filenames when actually dragging an image.

content/public/common/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/buildflag_header.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
@@ skipping 241 matching lines @@
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/interfaces",
     "//third_party/WebKit/public:blink_headers",
     "//ui/accessibility",
     "//ui/surface",
     "//url/ipc:url_ipc",
   ]
   deps = [
     # This looks needless as we have //content/common in public_deps, but it's
     # needed because of allow_circular_includes_from.
+    "//components/mime_util",
     "//content/common:mojo_bindings",
     "//ipc",
     "//media",
     "//mojo/common",
     "//net",
     "//ppapi/c",
     "//ppapi/features",
     "//services/service_manager/public/cpp",
     "//skia",
     "//storage/common",
@@ skipping 53 matching lines @@
   sources = [
     "window_container_type.mojom",
   ]
 }
 
 mojom("service_names") {
   sources = [
     "service_names.mojom",
   ]
 }