Add wait to testBrowsingPostEntryWithKeyboard.

ios/chrome/browser/web/browsing_egtest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <XCTest/XCTest.h>
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/ios/ios_util.h"
@@ skipping 609 matching lines @@
   GREYAssert([condition waitWithTimeout:10],
              @"No keyboard with 'Go' button showed up.");
 
   [[EarlGrey selectElementWithMatcher:grey_accessibilityID(@"Go")]
       performAction:grey_tap()];
 
   // Reenable synchronization now that the keyboard has been closed.
   [[GREYConfiguration sharedInstance]
           setValue:@YES
       forConfigKey:kGREYConfigKeySynchronizationEnabled];
+
+  // Ensure that the new page loaded before continuing.
+  [ChromeEarlGrey waitForPageToFinishLoading];

[Eugene But (OOO till 7-30), 2017/04/05 04:52:41]

According to API contract this method just enters the text and taps Go. It's not
suppose to wait for page load or even know that Go initiates a form submission.
Do you want to move this wait call to the test instead?

[gchatz, 2017/04/05 23:43:53]

In order for Go to be in the keyboard, the textfield is linked to a form
submission. I would prefer to just specify this in the comments, and leave the
wait here. 

[Eugene But (OOO till 7-30), 2017/04/06 00:28:18]

The method name is |openKeyboardAndTapGoButtonWithTextFieldID:|, so it does not
imply form submission or waiting for the load to finish. If you want this method
to wait, then how about renaming it to reflect it's actual functionality (form
submission)?

 }
 
 // Tests that submitting a POST-based form by tapping the 'Go' button on the
 // keyboard navigates to the correct URL and the back button works as expected
 // afterwards.
 // TODO(crbug.com/704618): Re-enable this test when the flake is fixed.
 - (void)FLAKY_testBrowsingPostEntryWithKeyboard {
   // Create map of canned responses and set up the test HTML server.
   std::map<GURL, std::string> responses;
   const GURL URL =
@@ skipping 22 matching lines @@
   [[EarlGrey selectElementWithMatcher:OmniboxText(destinationURL.GetContent())]
       assertWithMatcher:grey_notNil()];
 
   // Go back and verify that the browser navigates to the original URL.
   [self goBack];
   [[EarlGrey selectElementWithMatcher:OmniboxText(URL.GetContent())]
       assertWithMatcher:grey_notNil()];
 }
 
 @end