Explicitly set custom F# VS settings if they are missing

On package load, check if any of the custom F# settings are somehow missing
from the settings store.  Explicitly set them to their desired defaults if
they are indeed missing.

I've added this to the language service package since this is guaranteed
to load any time the project system package is loaded, but the converse is
not true (e.g. open loose F# script file without opening a solution).

fixes dotnet#199

vsintegration/src/vs/FsPkgs/FSharp.LanguageService/FSharp.LanguageService.fsproj

@@ -71,6 +71,7 @@
     <Reference Include="Microsoft.VisualStudio.Shell.Interop.10.0.dll" />
     <Reference Include="Microsoft.VisualStudio.Shell.Interop.dll" />
     <Reference Include="Microsoft.VisualStudio.Shell.Design, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+    <Reference Include="Microsoft.VisualStudio.Utilities, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
     <Reference Include="Microsoft.VisualStudio.Package.LanguageService.$(VisualStudioVersion)" />
     <Reference Include="Microsoft.VisualStudio.Shell.Immutable.11.0" />
     <Reference Include="Microsoft.VisualStudio.ProjectAggregator" />

vsintegration/src/vs/FsPkgs/FSharp.LanguageService/servicem.fs

@@ -1992,6 +1992,11 @@ module Setup =
                 context.RemoveKey(providerRegKey())
 #endif
 
+// Workaround to access non-public settings persistence type.
+// GetService( ) with this will work as long as the GUID matches the real type.
+[<Guid("9B164E40-C3A2-4363-9BC5-EB4039DEF653")>]
+type internal SVsSettingsPersistenceManager = class end
+
 [<Guid("871D2A70-12A2-4e42-9440-425DD92A4116")>]
 type FSharpPackage() as self =
     inherit Package()
@@ -2016,12 +2021,32 @@ type FSharpPackage() as self =
     let callback = new ServiceCreatorCallback(CreateIfEnabled)
 
     let mutable mgr : IOleComponentManager = null
+
+    let fsharpSpecificProfileSettings =
+        [| "TextEditor.F#.Insert Tabs", box false
+           "TextEditor.F#.Brace Completion", box true
+           "TextEditor.F#.Indent Style", box 1u |]
 
     override self.Initialize() =
         UIThread.CaptureSynchronizationContext()
+        self.EstablishDefaultSettingsIfMissing()
         (self :> IServiceContainer).AddService(typeof<FSharpLanguageService>, callback, true)
         base.Initialize()
 
+    /// In case custom VS profile settings for F# are not applied, explicitly set them here.
+    /// e.g. 'keep tabs' is the text editor default, but F# requires 'insert spaces'.
+    /// We specify our customizations in the General profile for VS, but we have found that in some cases
+    /// those customizations are incorrectly ignored.
+    member private this.EstablishDefaultSettingsIfMissing() =
+        let settingsManager = this.GetService(typeof<SVsSettingsPersistenceManager>) :?> Microsoft.VisualStudio.Settings.ISettingsManager
+        for settingName,defaultValue in fsharpSpecificProfileSettings do
+            // Only take action if the setting has no current custom value
+            // If cloud-synced settings have already been applied or the user has made an explicit change, do nothing
+            match settingsManager.TryGetValue(settingName) with
+            | Microsoft.VisualStudio.Settings.GetValueResult.Missing, _ ->
+                settingsManager.SetValueAsync(settingName, defaultValue, false) |> ignore
+            | _ -> ()
+
     member self.RegisterForIdleTime() =
         mgr <- (self.GetService(typeof<SOleComponentManager>) :?> IOleComponentManager)
         if (componentID = 0u && mgr <> null) then