[Extensions] Add a basic browser test for ScriptExecutor

ScriptExecutor is used to drive programmatic script execution by
extensions into different web frames. While it is reasonably tested
transitively through end-to-end tests for the tabs.executeScript()
method and friends, we should have more targetted testing for its
functionality as well.

Add a browser test with a simple test case of injecting script into
the main world and returning the result as a starting point.

Bug: None
Change-Id: I9a00a6b1141935d35cf1c0317c0ccda734c991e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2528912
Auto-Submit: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: David Bertoni <dbertoni@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826365}

chrome/browser/extensions/script_executor_browsertest.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+
+#include "base/strings/utf_string_conversions.h"
+#include "base/test/bind.h"
+#include "base/values.h"
+#include "chrome/browser/extensions/extension_browsertest.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test.h"
+#include "content/public/test/test_navigation_observer.h"
+#include "extensions/browser/extension_api_frame_id_map.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/script_executor.h"
+#include "extensions/common/extension_builder.h"
+#include "extensions/common/user_script.h"
+#include "net/dns/mock_host_resolver.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+class ScriptExecutorBrowserTest : public ExtensionBrowserTest {
+ public:
+  ScriptExecutorBrowserTest() = default;
+  ScriptExecutorBrowserTest(const ScriptExecutorBrowserTest&) = delete;
+  ScriptExecutorBrowserTest& operator=(const ScriptExecutorBrowserTest&) =
+      delete;
+  ~ScriptExecutorBrowserTest() override = default;
+
+  const Extension* LoadExtensionWithHostPermission(
+      const std::string& host_permission) {
+    scoped_refptr<const Extension> extension =
+        ExtensionBuilder("extension").AddPermission(host_permission).Build();
+    extension_service()->AddExtension(extension.get());
+    EXPECT_TRUE(
+        extension_registry()->enabled_extensions().GetByID(extension->id()));
+    return extension.get();
+  }
+
+  void SetUpOnMainThread() override {
+    ExtensionBrowserTest::SetUpOnMainThread();
+    host_resolver()->AddRule("*", "127.0.0.1");
+    ASSERT_TRUE(embedded_test_server()->Start());
+  }
+};
+
+IN_PROC_BROWSER_TEST_F(ScriptExecutorBrowserTest, MainFrameExecution) {
+  const Extension* extension =
+      LoadExtensionWithHostPermission("http://example.com/*");
+
+  GURL example_com =
+      embedded_test_server()->GetURL("example.com", "/simple.html");
+  content::WebContents* web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  ASSERT_TRUE(web_contents);
+
+  {
+    content::TestNavigationObserver nav_observer(web_contents);
+    ui_test_utils::NavigateToURL(browser(), example_com);
+    nav_observer.Wait();
+    EXPECT_TRUE(nav_observer.last_navigation_succeeded());
+  }
+
+  EXPECT_EQ("OK", base::UTF16ToUTF8(web_contents->GetTitle()));
+
+  ScriptExecutor script_executor(web_contents);
+  constexpr char kCode[] =
+      R"(let oldTitle = document.title;
+         document.title = 'New Title';
+         oldTitle;
+        )";
+
+  std::string execution_error("<initial error>");
+  GURL execution_url;
+  base::Value execution_result;
+  base::RunLoop run_loop;
+  auto script_finished = [&execution_error, &execution_url, &execution_result,
+                          &run_loop](const std::string& error, const GURL& url,
+                                     const base::ListValue& value) {
+    execution_error = error;
+    execution_url = url;
+    execution_result = value.Clone();
+    run_loop.Quit();
+  };
+
+  script_executor.ExecuteScript(
+      HostID(HostID::EXTENSIONS, extension->id()), UserScript::ADD_JAVASCRIPT,
+      kCode, ScriptExecutor::SINGLE_FRAME, ExtensionApiFrameIdMap::kTopFrameId,
+      ScriptExecutor::DONT_MATCH_ABOUT_BLANK, UserScript::DOCUMENT_IDLE,
+      ScriptExecutor::DEFAULT_PROCESS, GURL() /* webview_src */,
+      GURL() /* script_url */, false /* user_gesture */,
+      base::nullopt /* css_origin */, ScriptExecutor::JSON_SERIALIZED_RESULT,
+      base::BindLambdaForTesting(script_finished));
+  run_loop.Run();
+  EXPECT_EQ("New Title", base::UTF16ToUTF8(web_contents->GetTitle()));
+  EXPECT_EQ(web_contents->GetLastCommittedURL(), execution_url);
+  EXPECT_EQ("", execution_error);
+
+  base::Value expected(base::Value::Type::LIST);
+  expected.Append("OK");
+  EXPECT_EQ(expected, execution_result);
+}
+
+}  // namespace extensions

chrome/test/BUILD.gn

@@ -2052,6 +2052,7 @@ if (!is_android) {
         "../browser/extensions/process_manager_browsertest.cc",
         "../browser/extensions/renderer_initialization_browsertest.cc",
         "../browser/extensions/sandboxed_pages_apitest.cc",
+        "../browser/extensions/script_executor_browsertest.cc",
         "../browser/extensions/service_worker_apitest.cc",
         "../browser/extensions/service_worker_messaging_apitest.cc",
         "../browser/extensions/shared_module_apitest.cc",