Add xcprivacy privacy manifest to iOS framework (flutter#48951)

Create a `PrivacyInfo.xcprivacy` (this name is required) plist and move it to the top-level of the iOS framework bundle.  `NSPrivacyTracking*` and `NSPrivacyCollectedDataTypes` keys are required, but the values are blank.

Apple [now requires](https://developer.apple.com/documentation/bundleresources/privacy_manifest_files) that third-party frameworks must include this manifest to document usage of particular APIs and [how they are used](https://developer.apple.com/documentation/bundleresources/privacy_manifest_files/describing_use_of_required_reason_api).

> Starting in fall 2023, when you upload a new app or app update to App Store Connect that uses an API (including from third-party SDKs) that requires a reason, you�ll receive a notice if you haven�t provided an approved reason in your app�s privacy manifest. And starting in spring 2024, in order to upload your new app or app update to App Store Connect, you�ll be required to include an approved reason in the app�s privacy manifest which accurately reflects how your app uses the API.

https://developer.apple.com/news/?id=z6fu1dcu

@stuartmorgan [audited](flutter/flutter#131494 (comment)) the engine and third_party:

> * File timestamps:
>   
>   * `C617.1` for app state restoration in `FlutterAppDelegate.mm`.
>   * `0A2A.1` for implementation of the relevant `File` wrappers.
> * System boot time:
>   
>   * `35F9.1` for various event timing and elapsed time calculations.

Note macOS frameworks do not need to declare `NSPrivacyAccessedAPITypes`.
I don't think this will require recipe or conductor codesign changes since this is a file copied as a resource into the framework, just as the modulemap and Info.plist aren't referenced anywhere.

I'm not quite sure how to test this other than letting it build and generate a `Generate Privacy Report` in a Flutter app in Xcode.  There's no where we check that, say, the Info.plist is copied to the right place in Flutter.framework (even in flutter/flutter).  When this rolls into the framework I will add a check to [ios_content_validation_test.dart](https://github.com/flutter/flutter/blob/3da9bc169837d223496439b6d5f6b7e1a82d4318/dev/devicelab/bin/tasks/ios_content_validation_test.dart)

On this PR the `PrivacyInfo.xcprivacy` was written to the expected location in the Flutter.framework:
https://cas-viewer.appspot.com/projects/chromium-swarm/instances/default_instance/blobs/d45cd0809420f08145c7b78ea96cba6e7ea48d8ecfdc8fd2411f82fa65444714/516/tree

Fixes flutter/flutter#131494

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: jmagman

ci/licenses_golden/licenses_flutter

@@ -2543,6 +2543,7 @@ FILE: ../../../flutter/shell/platform/darwin/ios/framework/Headers/FlutterPlugin
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Headers/FlutterPluginAppLifeCycleDelegate.h
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Info.plist
+FILE: ../../../flutter/shell/platform/darwin/ios/framework/PrivacyInfo.xcprivacy
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegateTest.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/FlutterAppDelegate_Test.h

shell/platform/darwin/ios/BUILD.gn

@@ -348,6 +348,15 @@ copy("copy_framework_module_map") {
   outputs = [ "$_flutter_framework_dir/Modules/module.modulemap" ]
 }
 
+# Copy privacy manifest. This file is required by Apple for third-party SDKs,
+# and documents engine and third_party usage of timestamps and boot time APIs.
+# See https://developer.apple.com/documentation/bundleresources/privacy_manifest_files
+copy("copy_framework_privacy_manifest") {
+  visibility = [ ":*" ]
+  sources = [ "framework/PrivacyInfo.xcprivacy" ]
+  outputs = [ "$_flutter_framework_dir/PrivacyInfo.xcprivacy" ]
+}
+
 action("copy_framework_headers") {
   script = "//flutter/sky/tools/install_framework_headers.py"
   visibility = [ ":*" ]
@@ -387,6 +396,7 @@ shared_library("copy_and_verify_framework_module") {
     ":copy_framework_headers",
     ":copy_framework_info_plist",
     ":copy_framework_module_map",
+    ":copy_framework_privacy_manifest",
   ]
 }
 
@@ -398,6 +408,7 @@ group("universal_flutter_framework") {
     ":copy_framework_icu",
     ":copy_framework_info_plist",
     ":copy_framework_module_map",
+    ":copy_framework_privacy_manifest",
     ":copy_license",
   ]
 

shell/platform/darwin/ios/framework/PrivacyInfo.xcprivacy

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>NSPrivacyTracking</key>
+	<false/>
+	<key>NSPrivacyTrackingDomains</key>
+	<array/>
+	<key>NSPrivacyCollectedDataTypes</key>
+	<array>
+		<dict/>
+	</array>
+	<key>NSPrivacyAccessedAPITypes</key>
+	<array>
+		<dict>
+			<key>NSPrivacyAccessedAPIType</key>
+			<string>NSPrivacyAccessedAPICategoryFileTimestamp</string>
+			<key>NSPrivacyAccessedAPITypeReasons</key>
+			<array>
+				<string>0A2A.1</string>
+				<string>C617.1</string>
+			</array>
+		</dict>
+		<dict>
+			<key>NSPrivacyAccessedAPIType</key>
+			<string>NSPrivacyAccessedAPICategorySystemBootTime</string>
+			<key>NSPrivacyAccessedAPITypeReasons</key>
+			<array>
+				<string>35F9.1</string>
+			</array>
+		</dict>
+	</array>
+</dict>
+</plist>