Adds mailto: URL support to app launching.

ios/chrome/browser/web/BUILD.gn

 # Copyright 2016 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("//ios/web/js_compile.gni")
 
 source_set("web") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "dom_altering_lock.h",
     "dom_altering_lock.mm",
+    "mailto_handler.h",
+    "mailto_handler.mm",
+    "mailto_handler_gmail.h",
+    "mailto_handler_gmail.mm",
+    "mailto_handler_system_mail.h",
+    "mailto_handler_system_mail.mm",
+    "mailto_url_rewriter.h",
+    "mailto_url_rewriter.mm",
     "navigation_manager_util.h",
     "navigation_manager_util.mm",
     "network_activity_indicator_tab_helper.h",
     "network_activity_indicator_tab_helper.mm",
     "repost_form_tab_helper.h",
     "repost_form_tab_helper.mm",
     "sad_tab_tab_helper.h",
     "sad_tab_tab_helper.mm",
   ]
   deps = [
     ":sad_tab_tab_helper_delegate",
     "//base",
     "//components/strings",
+    "//ios/chrome/app/strings:ios_strings_grit",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/alert_coordinator:alert_coordinator",
     "//ios/chrome/browser/ui/commands:commands",
     "//ios/chrome/browser/ui/sad_tab:sad_tab",
     "//ios/chrome/browser/ui/util:util",
     "//ios/web",
     "//ios/web:web_arc",
     "//ui/base",
+    "//url",
   ]
 }
 
 source_set("sad_tab_tab_helper_delegate") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "sad_tab_tab_helper_delegate.h",
   ]
 }
 
 source_set("unit_tests") {
   configs += [ "//build/config/compiler:enable_arc" ]
   testonly = true
   sources = [
+    "mailto_handler_gmail_unittest.mm",
+    "mailto_handler_system_mail_unittest.mm",
+    "mailto_handler_unittest.mm",
+    "mailto_url_rewriter_unittest.mm",
     "navigation_manager_util_unittest.mm",
     "network_activity_indicator_tab_helper_unittest.mm",
     "repost_form_tab_helper_unittest.mm",
     "sad_tab_tab_helper_unittest.mm",
   ]
   deps = [
     ":sad_tab_tab_helper_delegate",
     ":web",
     "//base:base",
     "//base/test:test_support",
@@ skipping 148 matching lines @@
     "//components/version_info",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser",
     "//ios/chrome/browser:browser_impl",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/content_settings",
     "//ios/chrome/browser/infobars",
     "//ios/chrome/browser/ssl",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/ui/commands",
-    "//ios/chrome/browser/ui/overscroll_actions",
     "//ios/chrome/browser/ui/static_content",
+    "//ios/chrome/browser/web",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser/voice",
     "//ios/third_party/material_components_ios",
     "//ios/web",
     "//ios/web:user_agent",
     "//net",
     "//ui/base",
     "//ui/gfx",
     "//url",
   ]
@@ skipping 101 matching lines @@
     "early_page_script_perftest.mm",
   ]
   deps = [
     "//base",
     "//ios/chrome/test/base:perf_test_support",
     "//ios/web",
     "//ios/web:test_support",
   ]
   libs = [ "WebKit.framework" ]
 }