Revert "MD Extensions: Port LazyBackgroundPageApiTest.UpdateExtensionsPage to new UI."

This reverts commit 8d170b87.

Reason for revert: The test added by this CL is flaky.

Original change's description:
> MD Extensions: Port LazyBackgroundPageApiTest.UpdateExtensionsPage to new UI.
> 
> Bug: 800502
> Change-Id: I059c10360312df02b040e3e87667b8a39abce09c
> Reviewed-on: https://chromium-review.googlesource.com/891627
> Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
> Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#532714}

TBR=rdevlin.cronin@chromium.org,dpapad@chromium.org

Change-Id: I58b2acc0496a3c901e57fc240d96059ff50248ed
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 800502, 807153
Reviewed-on: https://chromium-review.googlesource.com/892658Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532772}

chrome/browser/extensions/lazy_background_page_apitest.cc

@@ -22,11 +22,9 @@
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/location_bar/location_bar.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
-#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/api/tabs.h"
-#include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "components/app_modal/javascript_app_modal_dialog.h"
@@ -621,82 +619,6 @@ IN_PROC_BROWSER_TEST_F(LazyBackgroundPageApiTest, UpdateExtensionsPage) {
         "    ele[0].innerHTML.search('(Inactive)') > 0);",
         &is_inactive));
   }
-  EXPECT_TRUE(is_inactive);
-}
-
-// TODO(dpapad): Remove the _MD suffix once the non-MD test is deleted.
-IN_PROC_BROWSER_TEST_F(LazyBackgroundPageApiTest, UpdateExtensionsPage_MD) {
-  base::test::ScopedFeatureList scoped_feature_list;
-  scoped_feature_list.InitWithFeatures(
-      {features::kMaterialDesignExtensions} /* enabled */, {} /* disabled */);
-
-  // Need to turn on developer mode, otherwise the info to be tested is not
-  // displayed in chrome://extensions.
-  browser()->profile()->GetPrefs()->SetBoolean(
-      prefs::kExtensionsUIDeveloperMode, true);
-
-  // Need to get the extension ID first, before opening the corresponding
-  // details page on chrome://extensions.
-  ui_test_utils::NavigateToURL(browser(), GURL(url::kAboutBlankURL));
-  ResultCatcher catcher;
-  base::FilePath extdir = test_data_dir_.AppendASCII("lazy_background_page")
-                              .AppendASCII("wait_for_view");
-  const Extension* extension = LoadExtension(extdir);
-  ASSERT_TRUE(extension);
-  EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
-
-  // The extension should've opened a new tab to an extension page.
-  EXPECT_EQ(
-      extension->GetResourceURL("extension_page.html").spec(),
-      browser()->tab_strip_model()->GetActiveWebContents()->GetURL().spec());
-
-  browser()->tab_strip_model()->ActivateTabAt(0, false);
-  std::string details_page_url = chrome::kChromeUIExtensionsURL;
-  details_page_url += "?id=" + extension->id();
-  ui_test_utils::NavigateToURL(browser(), GURL(details_page_url));
-  auto* extensions_page = browser()->tab_strip_model()->GetActiveWebContents();
-
-  // Lazy Background Page still exists, because the extension created a new tab
-  // to an extension page.
-  EXPECT_TRUE(IsBackgroundPageAlive(last_loaded_extension_id()));
-
-  // Close the new tab.
-  LazyBackgroundObserver page_complete;
-  browser()->tab_strip_model()->CloseWebContentsAt(1,
-                                                   TabStripModel::CLOSE_NONE);
-  page_complete.WaitUntilClosed();
-
-  // Lazy Background Page has been shut down.
-  EXPECT_FALSE(IsBackgroundPageAlive(last_loaded_extension_id()));
-
-  // Updating the extensions page is a process that has back-and-forth
-  // communication (i.e., backend tells extensions page something changed,
-  // extensions page requests updated data, backend responds with updated data,
-  // and so forth). This makes it difficult to know for sure when the page is
-  // done updating, so just try a few times. We limit the total number of
-  // attempts so that a) the test *fails* (instead of times out), and b) we
-  // know we're not making a ridiculous amount of trips to update the page.
-  const char setup_js[] =
-      R"(const detailView = document.querySelector('extensions-manager').
-             shadowRoot.querySelector('extensions-detail-view');
-         const inspectableViews = detailView.shadowRoot.querySelector(
-             '#inspectable-views');
-        )";
-  EXPECT_TRUE(
-      content::ExecuteScript(extensions_page, base::StringPrintf(setup_js)));
-
-  bool is_inactive = false;
-  int kMaxTries = 10;
-  int num_tries = 0;
-
-  while (!is_inactive && num_tries++ < kMaxTries) {
-    EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
-        extensions_page,
-        "window.domAutomationController.send("
-        "    inspectableViews.innerHTML.includes('(Inactive)'));",
-        &is_inactive));
-  }
-  EXPECT_TRUE(is_inactive);
 }
 
 // Tests that the lazy background page will be unloaded if the onSuspend event