Create DevToolsHttp and basic DevToolsClientBackend.

tools/telemetry/telemetry/core/backends/chrome_inspector/devtools_client_backend_unittest.py

Index: tools/telemetry/telemetry/core/backends/chrome_inspector/devtools_client_backend_unittest.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome_inspector/devtools_client_backend_unittest.py b/tools/telemetry/telemetry/core/backends/chrome_inspector/devtools_client_backend_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..9b280d62c700d6c217e0d9e0bf551b9a6bc37640
--- /dev/null
+++ b/tools/telemetry/telemetry/core/backends/chrome_inspector/devtools_client_backend_unittest.py
@@ -0,0 +1,28 @@
+# Copyright 2014 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.
+
+from telemetry.core.backends.chrome_inspector import devtools_client_backend
+from telemetry.core.backends.chrome_inspector import devtools_http
+from telemetry.unittest_util import browser_test_case
+
+
+class DevToolsClientBackendTest(browser_test_case.BrowserTestCase):
+  @property
+  def _devtools_client(self):
+    return self._browser._browser_backend.devtools_client
+
+  def testGetChromeBranchNumber(self):
+    branch_num = self._devtools_client.GetChromeBranchNumber()
+    self.assertIsInstance(branch_num, int)
+    self.assertGreater(branch_num, 0)
+
+  def testIsAlive(self):
+    self.assertTrue(self._devtools_client.IsAlive())
+
+  def testIsNotAlive(self):
+    client = devtools_client_backend.DevToolsClientBackend(1000)
+    def StubRequest(*_, **__):
+      raise devtools_http.DevToolsClientConnectionError
+    client._devtools_http.Request = StubRequest
+    self.assertFalse(client.IsAlive())