feat(compiler): use typescript for resolving resource paths

This can also be customized via the new method `resourceNameToFileName` in the
`CompilerHost`.

packages/compiler/test/aot/test_util.ts

@@ -330,8 +330,15 @@ export class MockAotCompilerHost implements AotCompilerHost {
   private metadataCollector = new MetadataCollector();
   private metadataVisible: boolean = true;
   private dtsAreSource: boolean = true;
+  private resolveModuleNameHost: ts.ModuleResolutionHost;
 
-  constructor(private tsHost: MockCompilerHost) {}
+  constructor(private tsHost: MockCompilerHost) {
+    this.resolveModuleNameHost = Object.create(tsHost);
+    this.resolveModuleNameHost.fileExists = (fileName) => {
+      fileName = stripNgResourceSuffix(fileName);
+      return tsHost.fileExists(fileName);
+    };
+  }
 
   hideMetadata() { this.metadataVisible = false; }
 
@@ -369,11 +376,22 @@ export class MockAotCompilerHost implements AotCompilerHost {
     moduleName = moduleName.replace(EXT, '');
     const resolved = ts.resolveModuleName(
                            moduleName, containingFile.replace(/\\/g, '/'),
-                           {baseDir: '/', genDir: '/'}, this.tsHost)
+                           {baseDir: '/', genDir: '/'}, this.resolveModuleNameHost)
                          .resolvedModule;
     return resolved ? resolved.resolvedFileName : null;
   }
 
+  resourceNameToFileName(resourceName: string, containingFile: string) {
+    // Note: we convert package paths into relative paths to be compatible with the the
+    // previous implementation of UrlResolver.
+    if (resourceName && resourceName.charAt(0) !== '.' && !path.isAbsolute(resourceName)) {
+      resourceName = `./${resourceName}`;
+    }
+    const filePathWithNgResource =
+        this.moduleNameToFileName(addNgResourceSuffix(resourceName), containingFile);
+    return filePathWithNgResource ? stripNgResourceSuffix(filePathWithNgResource) : null;
+  }
+
   // AotSummaryResolverHost
   loadSummary(filePath: string): string|null { return this.tsHost.readFile(filePath); }
 
@@ -647,3 +665,11 @@ export function compile(
   }
   return {genFiles, outDir};
 }
+
+function stripNgResourceSuffix(fileName: string): string {
+  return fileName.replace(/\.\$ngresource\$.*/, '');
+}
+
+function addNgResourceSuffix(fileName: string): string {
+  return `${fileName}.$ngresource$`;
+}