[Telemetry] Port page cycler to Telemetry.

tools/telemetry/telemetry/inspector_page.py

Index: tools/telemetry/telemetry/inspector_page.py
diff --git a/tools/telemetry/telemetry/inspector_page.py b/tools/telemetry/telemetry/inspector_page.py
index 58afb4e8f4bb22337b0575740fde772de0617905..3f9701ce413a2696d5df04b5ac7da3c0b215fdd0 100644
--- a/tools/telemetry/telemetry/inspector_page.py
+++ b/tools/telemetry/telemetry/inspector_page.py
@@ -138,3 +138,15 @@ class InspectorPage(object):
     if snap:
       return png_bitmap.PngBitmap(snap['data'])
     return None
+
+  def GetCookieByName(self, name, timeout=60):
+    """Returns the value of the cookie by the given |name|."""
+    request = {
+        'method': 'Page.getCookies'
+        }
+    res = self._inspector_backend.SyncRequest(request, timeout)
+    cookies = res['result']['cookies']
+    for cookie in cookies:
+      if cookie['name'] == name:
+        return cookie['value']
+    return None