Expose thumbnails of pages to iOS share extensions.

ios/chrome/browser/ui/activity_services/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.
 
 bundle_data("assets") {
   sources = [
     "resources/activity_services_print.xcassets/Contents.json",
     "resources/activity_services_print.xcassets/activity_services_print.imageset/Contents.json",
     "resources/activity_services_print.xcassets/activity_services_print.imageset/activity_services_print-60@2x.png",
     "resources/activity_services_print.xcassets/activity_services_print.imageset/activity_services_print-60@3x.png",
@@ skipping 20 matching lines @@
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "activity_service_controller.h",
     "activity_service_controller.mm",
     "activity_type_util.h",
     "activity_type_util.mm",
     "appex_constants.h",
     "appex_constants.mm",
     "chrome_activity_item_source.h",
     "chrome_activity_item_source.mm",
+    "chrome_activity_item_thumbnail_generator.h",
+    "chrome_activity_item_thumbnail_generator.mm",
     "print_activity.h",
     "print_activity.mm",
     "reading_list_activity.h",
     "reading_list_activity.mm",
     "share_protocol.h",
     "share_to_data.h",
     "share_to_data.mm",
+    "share_to_data_builder.h",
+    "share_to_data_builder.mm",
   ]
   deps = [
     ":assets",
     ":resources",
     "//base",
     "//components/reading_list/core",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser",
+    "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/commands",
     "//net",
     "//ui/base",
     "//url",
   ]
   libs = [
     "MobileCoreServices.framework",
     "UIKit.framework",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "activity_service_controller_unittest.mm",
     "activity_type_util_unittest.mm",
+    "chrome_activity_item_thumbnail_generator_unittest.mm",
   ]
   deps = [
     ":activity_services",
     "//base",
     "//base/test:test_support",
     "//components/reading_list/core",
     "//ios/chrome/app/strings",
+    "//ios/chrome/browser/browser_state:test_support",
+    "//ios/chrome/browser/tabs",
     "//ios/web:test_support",
     "//testing/gtest",
     "//third_party/ocmock",
     "//ui/base",
+    "//ui/base:test_support",
   ]
 }
 
 source_set("eg_tests") {
   testonly = true
   sources = [
     "activity_service_controller_egtest.mm",
   ]
   deps = [
     "//base",
     "//components/strings",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui:ui_internal",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/third_party/material_components_ios",
     "//ios/web:test_support",
     "//ui/base",
   ]
   libs = [ "XCTest.framework" ]
 }