Added integration test to Chrome Proxy to verify direct connection on remote site timeout

tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py

Index: tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py
diff --git a/tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py b/tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py
index 04740c5d6e8b4a687c32f75fad053dce207efc57..2296ea5a9b80e5dc46c7af8442cef232fd037c00 100644
--- a/tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py
+++ b/tools/chrome_proxy/integration_tests/chrome_proxy_benchmark.py
@@ -10,6 +10,21 @@ from telemetry import benchmark
 DESKTOP_PLATFORMS = ['mac', 'linux', 'win', 'chromeos']
 WEBVIEW_PLATFORMS = ['android-webview', 'android-webview-shell']
 
+
+class ChromeProxyBypassOnTimeout(ChromeProxyBenchmark):
+  """Check that the proxy bypasses when endpoint times out.

[sclittle, 2016/08/09 21:31:31]

nit: instead of "endpoint", could you say "origin"? Just so it's clear that it's
not the proxy that's timing out.

[Robert Ogden, 2016/08/09 21:56:22]

Done.

+
+  If the endpoint site does not make an HTTP response in a reasonable

[sclittle, 2016/08/09 21:31:31]

nit: again, s/endpoint/origin/. "endpoint" is technically still correct, but
replace with "origin" for consistency.

[Robert Ogden, 2016/08/09 21:56:22]

Done.

+  amount of time, the proxy should bypass.
+  """
+  tag = 'timeout_bypass'
+  test = measurements.ChromeProxyBypassOnTimeout
+  page_set = pagesets.BypassOnTimeoutStorySet
+
+  @classmethod
+  def Name(cls):
+    return 'chrome_proxy_benchmark.timeout_bypass.timeout_bypass'
+
 class ChromeProxyClientType(ChromeProxyBenchmark):
   tag = 'client_type'
   test = measurements.ChromeProxyClientType
@@ -316,4 +331,4 @@ class ChromeProxyPingback(ChromeProxyBenchmark):
 
   @classmethod
   def Name(cls):
-    return 'chrome_proxy_benchmark.pingback'
+    return 'chrome_proxy_benchmark.pingback'