Add API Level 27.

Configuration.props

@@ -14,7 +14,7 @@
   <PropertyGroup>
     <ProductVersion>8.1.99</ProductVersion>
     <!-- *Latest* API level binding that we support; used when building src/Xamarin.Android.Build.Tasks -->
-    <AndroidLatestApiLevel Condition="'$(AndroidLatestApiLevel)' == ''">26</AndroidLatestApiLevel>
+    <AndroidLatestApiLevel Condition="'$(AndroidLatestApiLevel)' == ''">27</AndroidLatestApiLevel>
     <AndroidLatestFrameworkVersion Condition="'$(AndroidLatestFrameworkVersion)' == ''">v8.0</AndroidLatestFrameworkVersion>
     <!-- The API level and TargetFrameworkVersion for the default Mono.Android.dll build -->
     <AndroidApiLevel Condition=" '$(AndroidApiLevel)' == '' ">$(AndroidLatestApiLevel)</AndroidApiLevel>

build-tools/android-toolchain/android-toolchain.projitems

@@ -117,6 +117,10 @@
       <HostOS></HostOS>
       <DestDir>platforms\android-26</DestDir>
     </AndroidSdkItem>
+    <AndroidSdkItem Include="platform-27_r01.zip">
+      <HostOS></HostOS>
+      <DestDir>platforms\android-27</DestDir>
+    </AndroidSdkItem>
     <AndroidSdkItem Include="docs-24_r01.zip">
       <HostOS></HostOS>
       <DestDir>docs</DestDir>

build-tools/scripts/BuildEverything.mk

@@ -23,12 +23,12 @@ ZIP_OUTPUT            = $(ZIP_OUTPUT_BASENAME).$(ZIP_EXTENSION)
 ## The following values *must* use SPACE, **not** TAB, to separate values.
 
 # $(ALL_API_LEVELS) and $(ALL_FRAMEWORKS) must be kept in sync w/ each other
-ALL_API_LEVELS    = 1 2 3 4 5 6 7 8 9 10    11  12  13  14  15      16    17    18    19    20        21    22    23    24    25    26
+ALL_API_LEVELS    = 1 2 3 4 5 6 7 8 9 10    11  12  13  14  15      16    17    18    19    20        21    22    23    24    25    26  27
 # this was different from ALL_API_LEVELS when API Level 26 was "O". Same could happen in the future.
-ALL_PLATFORM_IDS  = 1 2 3 4 5 6 7 8 9 10    11  12  13  14  15      16    17    18    19    20        21    22    23    24    25    26
+ALL_PLATFORM_IDS  = 1 2 3 4 5 6 7 8 9 10    11  12  13  14  15      16    17    18    19    20        21    22    23    24    25    26  27
 # supported api levels
-ALL_FRAMEWORKS    = _ _ _ _ _ _ _ _ _ v2.3  _   _   _   _   v4.0.3  v4.1  v4.2  v4.3  v4.4  v4.4.87   v5.0  v5.1  v6.0  v7.0  v7.1  v8.0
-API_LEVELS        =                   10                    15      16    17    18    19    20        21    22    23    24    25    26
+ALL_FRAMEWORKS    = _ _ _ _ _ _ _ _ _ v2.3  _   _   _   _   v4.0.3  v4.1  v4.2  v4.3  v4.4  v4.4.87   v5.0  v5.1  v6.0  v7.0  v7.1  v8.0  v8.1
+API_LEVELS        =                   10                    15      16    17    18    19    20        21    22    23    24    25    26  27
 STABLE_API_LEVELS =                   10                    15      16    17    18    19    20        21    22    23    24    25    26
 
 ## The preceding values *must* use SPACE, **not** TAB, to separate values.

src/Mono.Android/Mono.Android.projitems

@@ -133,5 +133,11 @@
       <Id>26</Id>
       <Stable>True</Stable>
     </AndroidApiInfo>
+    <AndroidApiInfo Include="v8.1">
+      <Name>Oreo</Name>
+      <Level>27</Level>
+      <Id>27</Id>
+      <Stable>True</Stable>
+    </AndroidApiInfo>
   </ItemGroup>
 </Project>

src/Mono.Android/metadata

@@ -1381,6 +1381,25 @@
   <attr path="/api/package[@name='android.media']/interface[@name='MediaCas.EventListener']" name="argsType">MediaCasEventArgs</attr>
   <attr path="/api/package[@name='android.media']/interface[@name='MediaCas.EventListener']/method[@name='onEvent']/parameter[@name='MediaCas']" name="managedName">mediaCas</attr>
 
+  <!-- Until API Level 26, android.graphics.Color was static. In API Level 26,
+  it became instantiable and got instance members.
+
+  Xamarin.Android had wrong premise that android.graphics.Color can be totally
+  different thing and thus introduced completely different API with the same
+  type name. Wrong wrong wrong. It was wrong decision made back in 2010.
+
+  We will have to enable this line and bring back some sanity.
+  -->
+  <!-- attr path="/api/package[@name='android.graphics']/class[@name='Color']" name="managedName">AndroidColor</attr -->
+
+  <!-- API Level 27 -->
+
+  <!-- android.graphics.Color started to be in actual use and that uncovered
+  Xamarin.Android design mistake above! We have to remove WallpaperColors API
+  until Xamarin.Android fixes their bogus API design. -->
+  <remove-node path="/api/package[@name='android.app']/class[@name='WallpaperColors']" />
+
+
   <!-- detected field-property conflicts (e.g. see bug #60069)
 
   Some people think it's easy to implement "check and skip property generation" without trying to do,
@@ -1391,4 +1410,5 @@
   is the only way to go. For further changes we should completely rewrite everything.
    -->
   <attr path="/api/package[@name='android.os']/class[@name='Build']/method[@name='getSerial']" name="propertyName"></attr>
+
 </metadata>