Update some extension tests to use an unresolvable URL when using proxy.

This ensures that the request must go through the proxy to pass.

Bug: 901896
Change-Id: I4c54d438ab2689b082eefc544b1c64f3866bb2c9
Reviewed-on: https://chromium-review.googlesource.com/c/1354324Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612287}

chrome/browser/extensions/api/declarative_net_request/declarative_net_request_browsertest.cc

@@ -1351,8 +1351,9 @@ IN_PROC_BROWSER_TEST_P(DeclarativeNetRequestBrowserTest,
       ->FlushProxyConfigMonitorForTesting();
 
   // Verify that the extension can't intercept the network request.
-  ui_test_utils::NavigateToURL(browser(), embedded_test_server()->GetURL(
-                                              "/pages_with_script/page.html"));
+  ui_test_utils::NavigateToURL(
+      browser(),
+      GURL("http://does.not.resolve.test/pages_with_script/page.html"));
   EXPECT_TRUE(WasFrameWithScriptLoaded(GetMainFrame()));
   EXPECT_EQ(content::PAGE_TYPE_NORMAL, GetPageType());
 }

chrome/browser/extensions/api/web_request/web_request_apitest.cc

@@ -1256,8 +1256,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionWebRequestApiTest,
       ->FlushProxyConfigMonitorForTesting();
 
   // Navigate to a page. The URL doesn't matter.
-  ui_test_utils::NavigateToURL(browser(),
-                               embedded_test_server()->GetURL("/title2.html"));
+  ui_test_utils::NavigateToURL(
+      browser(), GURL("http://does.not.resolve.test/title2.html"));
 
   // The extension should not have seen the PAC request.
   EXPECT_EQ(0, GetCountFromBackgroundPage(extension, profile(),