React to aspnet/dnx#1905 and aspnet/dnx#1906.

- Removed PluginProtocolMessage because it's now handled by the PluginHandler in the DTH.
- Updated ProcessMessage to match the new IPlugin contract. This included indicating if a message was handled or not via the return message.
- Removed PluginProtocolMessage tests.
- Added handled checking to existing tests.

Author: N. Taylor Mullen

src/Microsoft.AspNet.Tooling.Razor/Models/OutgoingMessages/PluginProtocolMessage.cs

@@ -15,15 +15,16 @@ namespace Microsoft.AspNet.Tooling.Razor
 {
     public class RazorPlugin : IPlugin
     {
-        private static readonly Version Protocol = new Version(1, 0, 0);
         private readonly IPluginMessageBroker _messageBroker;
 
         public RazorPlugin(IPluginMessageBroker messageBroker)
         {
             _messageBroker = messageBroker;
         }
 
-        public void ProcessMessage(JObject data, IAssemblyLoadContext assemblyLoadContext)
+        public int Protocol { get; set; } = 1;
+
+        public bool ProcessMessage(JObject data, IAssemblyLoadContext assemblyLoadContext)
         {
             var message = data.ToObject<RazorPluginRequestMessage>();
 
@@ -37,9 +38,6 @@ public void ProcessMessage(JObject data, IAssemblyLoadContext assemblyLoadContex
 
             switch (message.MessageType)
             {
-                case RazorPluginMessageTypes.PluginProtocol:
-                    _messageBroker.SendMessage(new PluginProtocolMessage(Protocol));
-                    break;
                 case RazorPluginMessageTypes.ResolveTagHelperDescriptors:
                     if (message.Data == null)
                     {
@@ -86,7 +84,12 @@ public void ProcessMessage(JObject data, IAssemblyLoadContext assemblyLoadContex
 
                     _messageBroker.SendMessage(responseMessage);
                     break;
+                default:
+                    // Unknown message.
+                    return false;
             }
+
+            return true;
         }
     }
 }

src/Microsoft.AspNet.Tooling.Razor/RazorPlugin.cs

@@ -6,6 +6,5 @@ namespace Microsoft.AspNet.Tooling.Razor
     public static class RazorPluginMessageTypes
     {
         public const string ResolveTagHelperDescriptors = nameof(ResolveTagHelperDescriptors);
-        public const string PluginProtocol = nameof(PluginProtocol);
     }
 }

src/Microsoft.AspNet.Tooling.Razor/RazorPluginMessageTypes.cs

@@ -70,6 +70,7 @@ public void ProcessMessage_ThrowsWhenNoData()
         [Fact]
         public void ProcessMessage_NoOpsForUnknownMessageType()
         {
+            // Arrange
             var messageData = new JObject();
             var message = new JObject
             {
@@ -81,9 +82,12 @@ public void ProcessMessage_NoOpsForUnknownMessageType()
             var assemblyLoadContext = new TestAssemblyLoadContext();
             var plugin = new RazorPlugin(messageBroker);
 
-            plugin.ProcessMessage(message, assemblyLoadContext);
+            // Act
+            var handled = plugin.ProcessMessage(message, assemblyLoadContext);
 
+            // Assert
             Assert.False(called);
+            Assert.False(handled);
         }
 
         [Fact]
@@ -131,29 +135,6 @@ public void ProcessMessage_ResolveTagHelperDescriptors_ThrowsWhenNoSourceLocatio
             Assert.Equal(expectedMessage, error.Message, StringComparer.Ordinal);
         }
 
-        [Fact]
-        public void ProcessMessage_PluginProtocol_ResolvesCurrentProtocol()
-        {
-            // Arrange
-            var message = new JObject
-            {
-                { "MessageType", RazorPluginMessageTypes.PluginProtocol },
-            };
-            PluginProtocolMessage responseMessage = null;
-            var messageBroker = new TestPluginMessageBroker(data => responseMessage = (PluginProtocolMessage)data);
-            var assemblyLoadContext = new TestAssemblyLoadContext();
-            var plugin = new RazorPlugin(messageBroker);
-
-            // Act
-            plugin.ProcessMessage(message, assemblyLoadContext);
-
-            // Assert
-            Assert.NotNull(responseMessage);
-            Assert.Equal(RazorPluginMessageTypes.PluginProtocol, responseMessage.MessageType, StringComparer.Ordinal);
-            var responseData = responseMessage.Data;
-            Assert.Equal("1.0.0", responseData, StringComparer.Ordinal);
-        }
-
         [Fact]
         public void ProcessMessage_ResolveTagHelperDescriptors_ResolvesTagHelperDescriptors()
         {
@@ -182,7 +163,7 @@ public void ProcessMessage_ResolveTagHelperDescriptors_ResolvesTagHelperDescript
             var plugin = new RazorPlugin(messageBroker);
 
             // Act
-            plugin.ProcessMessage(message, assemblyLoadContext);
+            var handled = plugin.ProcessMessage(message, assemblyLoadContext);
 
             // Assert
             Assert.NotNull(responseMessage);
@@ -195,6 +176,7 @@ public void ProcessMessage_ResolveTagHelperDescriptors_ResolvesTagHelperDescript
             var actualDescriptor = Assert.Single(responseData.Descriptors);
             Assert.Equal(CustomTagHelperDescriptor, actualDescriptor, TagHelperDescriptorComparer.Default);
             Assert.Empty(responseData.Errors);
+            Assert.True(handled);
         }
 
         [Fact]
@@ -220,7 +202,7 @@ public void ProcessMessage_ResolveTagHelperDescriptors_ReturnsErrors()
             var plugin = new RazorPlugin(messageBroker);
 
             // Act
-            plugin.ProcessMessage(message, assemblyLoadContext);
+            var handled = plugin.ProcessMessage(message, assemblyLoadContext);
 
             // Assert
             Assert.NotNull(responseMessage);
@@ -238,6 +220,7 @@ public void ProcessMessage_ResolveTagHelperDescriptors_ReturnsErrors()
                 StringComparer.Ordinal);
             Assert.Equal(expectedSourceLocation, error.Location);
             Assert.Equal(1, error.Length);
+            Assert.True(handled);
         }
 
         private class ThrowingAssemblyLoadContext : TestAssemblyLoadContext, IAssemblyLoadContext