[filesapp] Serve UITest files from embedded test server

FileManager UITests fail when native HTML Imports are disabled. Serve
the test files from the embedded test server to make the HTML imports
polyfill on the UITest test.html page work.

The tests now pass when HTML imports are disabled. All console errors
about Polymer not working are gone.

The Visual Signals xf* files 404 off the embedded test server but the
UITests still PASS.

Test: browser_tests --gtest_filter="FileManagerUITest*"
Bug: 1111393
Change-Id: Iec0133c61b7296ced6bb01fb740e1667b9aa8d0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2515379
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823401}

chrome/browser/chromeos/file_manager/file_manager_uitest.cc

@@ -2,16 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/files/file_path.h"
 #include "base/path_service.h"
-#include "base/strings/stringprintf.h"
+#include "base/strings/strcat.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
-#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/browser_test.h"
 #include "content/public/test/browser_test_utils.h"
-#include "net/base/filename_util.h"
+#include "net/test/embedded_test_server/embedded_test_server.h"
 #include "third_party/blink/public/common/web_preferences/web_preferences.h"
 
 namespace file_manager {
@@ -20,19 +21,25 @@ namespace file_manager {
 class FileManagerUITest : public InProcessBrowserTest {
  public:
   void SetUpCommandLine(base::CommandLine* command_line) override {
-    // --disable-web-security required to load resources from files.
+    // --disable-web-security required to launch Worker.
     command_line->AppendSwitch(switches::kDisableWebSecurity);
   }
 
-  void RunTest(std::string test_scope) {
-    base::FilePath root_path;
-    ASSERT_TRUE(base::PathService::Get(base::DIR_MODULE, &root_path));
+  void RunTest(const char* name) {
+    base::FilePath out_dir;
+    CHECK(base::PathService::Get(base::DIR_EXE, &out_dir));
 
-    // Load test.html.
-    const GURL url = net::FilePathToFileURL(root_path.Append(
-        FILE_PATH_LITERAL("gen/ui/file_manager/file_manager/test.html")));
-    content::WebContents* const web_contents =
+    // Serve files from |gen_path|. Some files are read from DIR_SOURCE_ROOT
+    // so serve from there as well.
+    const base::FilePath gen_path =
+        out_dir.Append(FILE_PATH_LITERAL("gen/ui/file_manager/file_manager"));
+    embedded_test_server()->ServeFilesFromDirectory(gen_path);
+    embedded_test_server()->ServeFilesFromSourceDirectory(base::FilePath());
+    CHECK(embedded_test_server()->Start());
+
+    content::WebContents* web_contents =
         browser()->tab_strip_model()->GetActiveWebContents();
+    CHECK(web_contents);
 
     // Set prefs required for cut/paste.
     auto web_prefs = web_contents->GetOrCreateWebPreferences();
@@ -40,13 +47,13 @@ class FileManagerUITest : public InProcessBrowserTest {
     web_prefs.javascript_can_access_clipboard = true;
     web_contents->SetWebPreferences(web_prefs);
 
-    ASSERT_TRUE(web_contents);
-    ui_test_utils::NavigateToURL(browser(), url);
+    // Load test page.
+    GURL test_page = embedded_test_server()->GetURL("/test.html");
+    ui_test_utils::NavigateToURL(browser(), test_page);
 
-    // Load and run specified test file.
+    // Run test |name|.
     content::DOMMessageQueue message_queue;
-    ExecuteScriptAsync(web_contents,
-                       base::StringPrintf("runTests(%s)", test_scope.c_str()));
+    ExecuteScriptAsync(web_contents, base::StrCat({"runTests(", name, ")"}));
 
     // Wait for JS to call domAutomationController.send("SUCCESS").
     std::string message;