[Android][libraries] TimeZoneInfo Android imp

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -2084,7 +2084,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Security\SecureString.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\LowLevelMonitor.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\TimerQueue.Unix.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\TimeZoneInfo.Unix.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\TimeZoneInfo.AnyUnix.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\TimeZoneInfo.Android.cs" Condition="'$(TargetsAndroid)' == 'true'" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\TimeZoneInfo.Unix.cs" Condition="'$(TargetsAndroid)' != 'true'" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsUnix)' == 'true'">
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetEUid.cs">

src/libraries/System.Private.CoreLib/src/System/TimeZoneInfo.Android.cs

@@ -0,0 +1,53 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace System
+{
+    public sealed partial class TimeZoneInfo
+    {
+        private const string TimeZoneFileName = "tzdata";
+
+        private static string GetApexTimeDataRoot()
+        {
+            var ret = Environment.GetEnvironmentVariable("ANDROID_TZDATA_ROOT");
+            if (!string.IsNullOrEmpty(ret))
+            {
+                return ret;
+            }
+
+            return "/apex/com.android.tzdata";
+        }
+
+        private static string GetApexRuntimeRoot()
+        {
+            var ret = Environment.GetEnvironmentVariable("ANDROID_RUNTIME_ROOT");
+            if (!string.IsNullOrEmpty(ret))
+            {
+                return ret;
+            }
+
+            return "/apex/com.android.runtime";
+        }
+
+        internal static readonly string[] Paths = new string[] { GetApexTimeDataRoot() + "/etc/tz/", // Android 10+, TimeData module where the updates land
+                                                                 GetApexRuntimeRoot() + "/etc/tz/",  // Android 10+, Fallback location if the above isn't found or corrupted
+                                                                 Environment.GetEnvironmentVariable("ANDROID_DATA") + "/misc/zoneinfo/",};
+
+        private static string GetTimeZoneDirectory()
+        {
+            foreach (var filePath in Paths)
+            {
+                if (File.Exists(Path.Combine(filePath, "TimeZoneFileName")))
+                {
+                    return filePath;
+                }
+            }
+
+            return Environment.GetEnvironmentVariable("ANDROID_ROOT") + DefaultTimeZoneDirectory;
+        }
+    }
+}