Add integration tests for QUIC

tools/chrome_proxy/common/chrome_proxy_measurements.py

Index: tools/chrome_proxy/common/chrome_proxy_measurements.py
diff --git a/tools/chrome_proxy/common/chrome_proxy_measurements.py b/tools/chrome_proxy/common/chrome_proxy_measurements.py
index 58d7faa5a03c688da589466d2c640a268b189e1f..5e28754ba1040d0f227533770a0ff794e38504c4 100644
--- a/tools/chrome_proxy/common/chrome_proxy_measurements.py
+++ b/tools/chrome_proxy/common/chrome_proxy_measurements.py
@@ -80,9 +80,6 @@ class ChromeProxyValidation(page_test.PageTest):
     options.AppendExtraBrowserArgs('--enable-spdy-proxy-auth')
     self._is_chrome_proxy_enabled = True
 
-    # Disable quic option, otherwise request headers won't be visible.
-    options.AppendExtraBrowserArgs('--disable-quic')

[bustamante, 2016/09/21 18:50:12]

I think we need this for every test, since the quic experiment being enabled
(which was happening occasionally) blocks header validation.  For example, when
an integration test runs on staging all tests will validate that the "1.1
Chrome-Compression-Proxy-Testing" via header appears in responses.

[RyanSturm, 2016/09/21 18:56:24]

I think he adds the command individually to the tests that do header validation.

[bustamante, 2016/09/21 19:11:42]

All tests can do header validation if the --extra-chrome-proxy-via-header flag
is used.

But also I don't think it's obvious that someone has to know to add a
--disable-quic flag if they want to do header validation, so it's going to lead
to more flaking down the road - like crbug.com/593331

[tbansal1, 2016/09/22 17:25:42]

Looking at AddResultsForExtraViaHeader function, it seems it only checks the
response headers (and not the request headers). So, that should work correctly
even if QUIC is in use, since usage of QUIC only makes the request headers
difficult to look up.
For now, I have put this flag back. However, I have kept the --disable-quic in
the individual tests that actually look at the request headers. That way we can
easily remove the global --disable-quic flag in the future (if there is a need),
without breaking any tests.

-
   def DisableChromeProxy(self):
     self.options.browser_options.extra_browser_args.discard(
                 '--enable-spdy-proxy-auth')