Add lite page BTF test

tools/chrome_proxy/webdriver/lite_page.py

Index: tools/chrome_proxy/webdriver/lite_page.py
diff --git a/tools/chrome_proxy/webdriver/lite_page.py b/tools/chrome_proxy/webdriver/lite_page.py
index d7fe48aa6b8860f458d66fb7fe4ceac56b97e3d4..a9219e3525ff602f4a725d3405493557eb990409 100644
--- a/tools/chrome_proxy/webdriver/lite_page.py
+++ b/tools/chrome_proxy/webdriver/lite_page.py
@@ -6,6 +6,7 @@ import common
 from common import TestDriver
 from common import IntegrationTest
 
+import time
 
 class LitePage(IntegrationTest):
 
@@ -39,6 +40,49 @@ class LitePage(IntegrationTest):
       # Verify that a Lite Page response for the main frame was seen.
       self.assertEqual(1, lite_page_responses)
 
+  # Checks that a Lite Page does not have an error when scrolling to the bottom
+  # of the page and is able to load all resources.
+  def testLitePageBTF(self):
+    # If it was attempted to run with another experiment, skip this test.
+    if common.ParseFlags().browser_args and ('--data-reduction-proxy-experiment'
+        in common.ParseFlags().browser_args):
+      self.skipTest('This test cannot be run with other experiments.')
+    with TestDriver() as test_driver:
+      test_driver.AddChromeArg('--enable-spdy-proxy-auth')
+      test_driver.AddChromeArg('--data-reduction-proxy-lo-fi=always-on')
+      test_driver.AddChromeArg('--enable-data-reduction-proxy-lite-page')
+
+      # This page is long and has many media resources.
+      test_driver.LoadURL('http://check.googlezip.net/metrics/index.html')
+
+      # Verify that a Lite Page response for the main frame was seen.
+      lite_page_responses = 0
+      for response in test_driver.GetHTTPResponses():
+        # Skip CSI requests when validating Lite Page headers. CSI requests
+        # aren't expected to have LoFi headers.
+        if '/csi?' in response.url:
+          continue
+        if response.url.startswith('data:'):
+          continue
+        self.assertIn('exp=ignore_preview_blacklist',
+          response.request_headers['chrome-proxy'])
+        if (self.checkLitePageResponse(response)):
+          lite_page_responses = lite_page_responses + 1
+      self.assertEqual(1, lite_page_responses)
+
+      # Scroll to the bottom of the window and make sure there were more
+      # requests that were proxied.
+      scroll_js = 'window.scrollTo(0,Math.max(document.body.scrollHeight));'
+      test_driver.ExecuteJavascriptStatement(scroll_js)
+      # Give some time for loading after each scroll.
+      time.sleep(2)
+      test_driver.ExecuteJavascriptStatement(scroll_js)
+      time.sleep(2)
+      responses = test_driver.GetHTTPResponses(override_has_logs=True)
+      self.assertNotEqual(0, len(responses))
+      for response in responses:
+        self.assertHasChromeProxyViaHeader(response)
+
   # Checks that Lo-Fi images are used when the user is in the
   # DataCompressionProxyLitePageFallback field trial and a Lite Page is not
   # served.