Fix expectations for HostedAppTest.SubframeRedirectsToHostedApp

At some point the innerText of the test page gained a couple of newline
characters. This isn't important to the test so trim them out.
Also use EvalJs() instead of the deprecated ExecuteScript*().

Bug: 956047
Change-Id: I8a8a67dcef9838ba7350d17a8fb2b51ccb6bf043
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585746
Auto-Submit: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Jay Harris <harrisjay@chromium.org>
Commit-Queue: Jay Harris <harrisjay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654796}

chrome/browser/ui/extensions/hosted_app_browsertest.cc

@@ -795,11 +795,9 @@ IN_PROC_BROWSER_TEST_P(HostedAppTest, SubframeRedirectsToHostedApp) {
   // content.
   RenderFrameHost* subframe = content::ChildFrameAt(tab->GetMainFrame(), 0);
   EXPECT_EQ(app_url, subframe->GetLastCommittedURL());
-  std::string result;
-  EXPECT_TRUE(ExecuteScriptAndExtractString(
-      subframe, "window.domAutomationController.send(document.body.innerText);",
-      &result));
-  EXPECT_EQ("This page has no title.", result);
+  EXPECT_EQ(
+      "This page has no title.",
+      EvalJs(subframe, "document.body.innerText.trim();").ExtractString());
 }
 
 // Check that no assertions are hit when showing a permission request bubble.