[Telemetry] Fix page_cycler for pages with client side redirects.

tools/telemetry/telemetry/core/backends/chrome/inspector_page.py

Index: tools/telemetry/telemetry/core/backends/chrome/inspector_page.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/inspector_page.py b/tools/telemetry/telemetry/core/backends/chrome/inspector_page.py
index 8c4c6fe899bde6d376c99eab406b652c35a1de4f..dc3bf4cfa5ee48ab0edd08acdc7c32da276bf6b9 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/inspector_page.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/inspector_page.py
@@ -15,8 +15,12 @@ class InspectorPage(object):
         'Page',
         self._OnNotification,
         self._OnClose)
+
     self._navigation_pending = False
     self._navigation_url = ""
+    self._script_to_evaluate_on_commit = None
+    # Turn on notifications. We need them to get the Page.frameNavigated event.
+    self._EnablePageNotifications()

[qsr, 2014/01/07 16:22:15]

Enabling notification only after setting up the variable. The error on the bots
was about some local variable not existing on this class:

Traceback (most recent call last):
  File
"/usr/local/google/home/achuith/code/chrome/src/tools/telemetry/telemetry/core/backends/chrome/inspector_backend.py",
line 243, in _HandleNotification
    self._domain_handlers[domain_name][0](res)
  File
"/usr/local/google/home/achuith/code/chrome/src/tools/telemetry/telemetry/core/backends/chrome/inspector_page.py",
line 27, in _OnNotification
    if msg['method'] == 'Page.frameNavigated' and self._navigation_pending:
AttributeError: 'InspectorPage' object has no attribute '_navigation_pending'

 I guess this can happen if a notification is sent immediately by the browser.

 
   def _OnNotification(self, msg):
     logging.debug('Notification: %s', json.dumps(msg, indent=2))
@@ -32,16 +36,36 @@ class InspectorPage(object):
   def _OnClose(self):
     pass
 
-  def _EnablePageNotifications(self, timeout):
-    request = {
-        'method': 'Page.enable'
-        }
-    res = self._inspector_backend.SyncRequest(request, timeout)
-    assert len(res['result'].keys()) == 0
+  def _SetScriptToEvaluateOnCommit(self, source):
+    existing_source = (self._script_to_evaluate_on_commit and
+                       self._script_to_evaluate_on_commit['source'])
+    if source == existing_source:
+      return
+    if existing_source:
+      request = {
+          'method': 'Page.removeScriptToEvaluateOnLoad',
+          'params': {
+              'identifier': self._script_to_evaluate_on_commit['id'],
+              }
+          }
+      self._inspector_backend.SyncRequest(request)
+      self._script_to_evaluate_on_commit = None
+    if source:
+      request = {
+          'method': 'Page.addScriptToEvaluateOnLoad',
+          'params': {
+              'scriptSource': source,
+              }
+          }
+      res = self._inspector_backend.SyncRequest(request)
+      self._script_to_evaluate_on_commit = {
+          'id': res['result']['identifier'],
+          'source': source
+          }
 
-  def _DisablePageNotifications(self, timeout):
+  def _EnablePageNotifications(self, timeout=60):
     request = {
-        'method': 'Page.disable'
+        'method': 'Page.enable'
         }
     res = self._inspector_backend.SyncRequest(request, timeout)
     assert len(res['result'].keys()) == 0
@@ -55,19 +79,15 @@ class InspectorPage(object):
     start_time = time.time()
     remaining_time = timeout
 
+    action_function()
+    self._navigation_pending = True
     try:
-      self._EnablePageNotifications(remaining_time)
-      try:
-        action_function()
-        self._navigation_pending = True
-        while self._navigation_pending and remaining_time > 0:
-          remaining_time = max(timeout - (time.time() - start_time), 0.0)
-          self._inspector_backend.DispatchNotifications(remaining_time)
-      finally:
-        self._DisablePageNotifications(remaining_time)
+      while self._navigation_pending and remaining_time > 0:
+        remaining_time = max(timeout - (time.time() - start_time), 0.0)
+        self._inspector_backend.DispatchNotifications(remaining_time)
     except util.TimeoutException:
-      # Since we pass remaining_time as timeout to all of the calls in this,
-      # method, we need to list the full timeout time in this message.
+      # Since we pass remaining_time to DispatchNotifications, we need to
+      # list the full timeout time in this message.
       raise util.TimeoutException('Timed out while waiting %ds for navigation. '
                                   'Error=%s' % (timeout, sys.exc_info()[1]))
 
@@ -80,14 +100,7 @@ class InspectorPage(object):
     """
 
     def DoNavigate():
-      if script_to_evaluate_on_commit:
-        request = {
-            'method': 'Page.addScriptToEvaluateOnLoad',
-            'params': {
-                'scriptSource': script_to_evaluate_on_commit,
-                }
-            }
-        self._inspector_backend.SyncRequest(request)
+      self._SetScriptToEvaluateOnCommit(script_to_evaluate_on_commit)
       # Navigate the page. However, there seems to be a bug in chrome devtools
       # protocol where the request id for this event gets held on the browser
       # side pretty much indefinitely.