Rename mojo_html_viewer target to just html_viewer.

mojo/services/html_viewer/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.
 
-# GYP version: mojo/mojo_services.gypi:mojo_html_viewer
+# GYP version: mojo/mojo_services.gypi:html_viewer
 shared_library("html_viewer") {
-  output_name = "mojo_html_viewer"
-
   sources = [
     "blink_basic_type_converters.cc",
     "blink_basic_type_converters.h",
     "blink_input_events_type_converters.cc",
     "blink_input_events_type_converters.h",
     "blink_platform_impl.cc",
     "blink_platform_impl.h",
     "blink_url_request_type_converters.cc",
     "blink_url_request_type_converters.h",
     "html_viewer.cc",
@@ skipping 50 matching lines @@
     "//mojo/services/public/interfaces/navigation",
     "//mojo/services/public/interfaces/network",
     "//mojo/services/public/interfaces/surfaces",
     "//net",
     "//skia",
     "//third_party/WebKit/public:blink",
     "//ui/native_theme",
     "//url",
   ]
 }