[Extensions] Update ComponentLoaderTests to manifest v2

ComponentLoaderTests have been updated to manifest v2.
Remove the allowance for manifest v1 extensions.

Bug: 816679

Change-Id: Ic35a4f11840ea2194b16f93eb541aa62e8cd7361
Reviewed-on: https://chromium-review.googlesource.com/1025134Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553220}

chrome/browser/extensions/component_loader_unittest.cc

@@ -91,9 +91,6 @@ class ComponentLoaderTest : public testing::Test {
   }
 
   void SetUp() override {
-    // TODO(devlin): Remove this. See https://crbug.com/816679.
-    allow_legacy_extensions_ = Extension::allow_legacy_extensions_for_testing();
-
     extension_path_ =
         GetBasePath().AppendASCII("good")
                      .AppendASCII("Extensions")
@@ -119,7 +116,6 @@ class ComponentLoaderTest : public testing::Test {
   sync_preferences::TestingPrefServiceSyncable prefs_;
   TestingPrefServiceSimple local_state_;
   ComponentLoader component_loader_;
-  Extension::ScopedAllowLegacyExtensions allow_legacy_extensions_;
 
   // The root directory of the text extension.
   base::FilePath extension_path_;