The command line flag is now set during the test startup.

These two tests replaced the global command line object, which might
cause heap-use-after-free of the temporary object at the end of the
test. For instance, ChromeExtensionsClient::GetWebstoreUpdateURL()
tries to read the command line flags, and does so asynchronously, not
in the main thread of the test.

The proposed patch eliminates use of the ScopedExperimentalCommandLine
at the test scope level, thus minimizing the risk of improper access to
memory.

BUG=
R=finnur@chromium.org

Review URL: https://codereview.chromium.org/1752293002

Cr-Commit-Position: refs/heads/master@{#380096}

chrome/browser/extensions/crx_installer_browsertest.cc

@@ -203,24 +203,6 @@ class ManagementPolicyMock : public extensions::ManagementPolicy::Provider {
   }
 };
 
-// Appends "enable-experimental-extension-apis" to the command line for the
-// lifetime of this class.
-class ScopedExperimentalCommandLine {
- public:
-  ScopedExperimentalCommandLine()
-      : saved_(*base::CommandLine::ForCurrentProcess()) {
-    base::CommandLine::ForCurrentProcess()->AppendSwitch(
-        switches::kEnableExperimentalExtensionApis);
-  }
-
-  ~ScopedExperimentalCommandLine() {
-    *base::CommandLine::ForCurrentProcess() = saved_;
-  }
-
- private:
-  base::CommandLine saved_;
-};
-
 }  // namespace
 
 class ExtensionCrxInstallerTest : public ExtensionBrowserTest {
@@ -279,8 +261,6 @@ class ExtensionCrxInstallerTest : public ExtensionBrowserTest {
   // |record_oauth2_grant| is true.
   void CheckHasEmptyScopesAfterInstall(const std::string& ext_relpath,
                                        bool record_oauth2_grant) {
-    ScopedExperimentalCommandLine scope;
-
     scoped_ptr<MockPromptProxy> mock_prompt =
         CreateMockPromptProxyForBrowser(browser());
 
@@ -292,18 +272,6 @@ class ExtensionCrxInstallerTest : public ExtensionBrowserTest {
     ASSERT_TRUE(permissions.get());
   }
 
-  // Returns a FilePath to an unpacked "experimental" extension (a test
-  // Extension which requests the "experimental" permission).
-  base::FilePath PackExperimentalExtension() {
-    // We must modify the command line temporarily in order to pack an
-    // extension that requests the experimental permission.
-    ScopedExperimentalCommandLine scope;
-    base::FilePath test_path = test_data_dir_.AppendASCII("experimental");
-    base::FilePath crx_path = PackExtension(test_path);
-    CHECK(!crx_path.empty()) << "Extension not found at " << test_path.value();
-    return crx_path;
-  }
-
   void InstallWebAppAndVerifyNoErrors() {
     ExtensionService* service =
         extensions::ExtensionSystem::Get(browser()->profile())
@@ -328,6 +296,15 @@ class ExtensionCrxInstallerTest : public ExtensionBrowserTest {
   }
 };
 
+class ExtensionCrxInstallerTestWithExperimentalApis
+    : public ExtensionCrxInstallerTest {
+ protected:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    ExtensionCrxInstallerTest::SetUpCommandLine(command_line);
+    command_line->AppendSwitch(switches::kEnableExperimentalExtensionApis);
+  }
+};
+
 // This test is skipped on ChromeOS because it requires the NPAPI,
 // which is not available on that platform.
 #if !defined(OS_CHROMEOS)
@@ -349,8 +326,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest,
                        ExperimentalExtensionFromGallery) {
   // Gallery-installed extensions should have their experimental permission
   // preserved, since we allow the Webstore to make that decision.
-  base::FilePath crx_path = PackExperimentalExtension();
-  const Extension* extension = InstallExtensionFromWebstore(crx_path, 1);
+  const Extension* extension = InstallExtensionFromWebstore(
+      test_data_dir_.AppendASCII("experimental.crx"), 1);
   ASSERT_TRUE(extension);
   EXPECT_TRUE(extension->permissions_data()->HasAPIPermission(
       APIPermission::kExperimental));
@@ -360,27 +337,26 @@ IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest,
                        ExperimentalExtensionFromOutsideGallery) {
   // Non-gallery-installed extensions should lose their experimental
   // permission if the flag isn't enabled.
-  base::FilePath crx_path = PackExperimentalExtension();
-  const Extension* extension = InstallExtension(crx_path, 1);
+  const Extension* extension = InstallExtension(
+      test_data_dir_.AppendASCII("experimental.crx"), 1);
   ASSERT_TRUE(extension);
   EXPECT_FALSE(extension->permissions_data()->HasAPIPermission(
       APIPermission::kExperimental));
 }
 
-IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest,
+IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTestWithExperimentalApis,
                        ExperimentalExtensionFromOutsideGalleryWithFlag) {
   // Non-gallery-installed extensions should maintain their experimental
   // permission if the flag is enabled.
-  base::FilePath crx_path = PackExperimentalExtension();
-  ScopedExperimentalCommandLine scope;
-  const Extension* extension = InstallExtension(crx_path, 1);
+  const Extension* extension = InstallExtension(
+      test_data_dir_.AppendASCII("experimental.crx"), 1);
   ASSERT_TRUE(extension);
   EXPECT_TRUE(extension->permissions_data()->HasAPIPermission(
       APIPermission::kExperimental));
 }
 
-IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest, PlatformAppCrx) {
-  ScopedExperimentalCommandLine scope;
+IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTestWithExperimentalApis,
+                       PlatformAppCrx) {
   EXPECT_TRUE(InstallExtension(
       test_data_dir_.AppendASCII("minimal_platform_app.crx"), 1));
 }
@@ -429,12 +405,14 @@ IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest, PackAndInstallExtension) {
 #else
 #define MAYBE_GrantScopes GrantScopes
 #endif
-IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest, MAYBE_GrantScopes) {
+IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTestWithExperimentalApis,
+                       MAYBE_GrantScopes) {
   EXPECT_NO_FATAL_FAILURE(CheckHasEmptyScopesAfterInstall("browsertest/scopes",
                                                           true));
 }
 
-IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTest, DoNotGrantScopes) {
+IN_PROC_BROWSER_TEST_F(ExtensionCrxInstallerTestWithExperimentalApis,
+                       DoNotGrantScopes) {
   EXPECT_NO_FATAL_FAILURE(CheckHasEmptyScopesAfterInstall("browsertest/scopes",
                                                           false));
 }

chrome/test/data/extensions/experimental/manifest.json

-{
-  "name": "experimental test",
-  "version": "1",
-  "manifest_version": 2,
-  "permissions": ["experimental"]
-}