fix(language-service): remove tsickle dependency

Removes the tsickle dependency added when tsickle was added to the
transform compiler.

Added a test to ensure stray dependencies are not added and no
errors are introduced during module flattening.

integration/language_service_plugin/scripts/test.sh

@@ -9,6 +9,11 @@ source scripts/env.sh
 HOST="node tools/typescript_host.js"
 VALIDATE="node tools/typescript_validator.js"
 
+# Ensure the languages service can load correctly in node before typescript loads it.
+# This verifies its dependencies and emits any exceptions, both of which are  only  
+# emitted to the typescript logs (not the validated output).
+node tools/load_test.js
+
 for TYPESCRIPT in ${TYPESCRIPTS[@]}
 do
   SERVER="node typescripts/$TYPESCRIPT/node_modules/typescript/lib/tsserver.js"

integration/language_service_plugin/tools/load_test.ts

@@ -0,0 +1,35 @@
+const ts = require('typescript');
+const Module = require('module');
+
+const existingRequire = Module.prototype.require;
+
+const recordedRequires: string[] = [];
+
+function recordingRequire(path: string) {
+  recordedRequires.push(path);
+  return existingRequire.call(this, path);
+}
+
+Module.prototype.require = recordingRequire;
+
+try {
+  const lsf = require('@angular/language-service');
+  const ls = lsf({typescript: ts});
+
+  // Assert that the only module that should have been required are '@angular/langauge-service', 'fs', and 'path'
+
+  const allowedLoads = new Set(["@angular/language-service", "fs", "path"]);
+
+  const invalidModules = recordedRequires.filter(m => !allowedLoads.has(m));
+
+  if (invalidModules.length > 0) {
+    console.error(`FAILED: Loading the language service required: ${invalidModules.join(', ')}`);
+    process.exit(1);
+  }
+} catch (e) {
+  console.error(`FAILED: Loading the language service caused the following exception: ${e.stack || e}`);
+  process.exit(1);
+}
+
+console.log('SUCCESS: Loading passed')
+process.exit(0);

integration/language_service_plugin/tools/tsconfig.json

@@ -13,6 +13,7 @@
     },
     "files": [
         "typescript_host.ts", 
-        "typescript_validator.ts"
+        "typescript_validator.ts",
+        "load_test.ts"
     ]
 }