Reland: [Telemetry] Fix image_decoding_measurement timeout.

This was reverted because it caused some timeouts. The reland is the same as the
original but I now preseved the original timeout values of Page.enable and
Page.disable.

> util.WaitFor polls which is not appropriate for PerformActionAndWaitForNavigate.
>
> Since DispatchNotifications blocks in recv until it gets some data, there is no
> need to poll at an interval. Instead, we should call recv again as soon as
> possible after dispatching a notification.
>
> In the case of the image decoding measurement, it runs timeline recording. There
> were so many timeline messages to receive that we were not always getting to the
> important Page.navigate message before timing out.
>
> Example:
> http://build.chromium.org/p/chromium.perf/builders/Linux%20Perf%20%281%29/builds/27098
>
> BUG=314375
>
> Review URL: https://codereview.chromium.org/47013004

TBR=kbr@chromium.org
BUG=

Review URL: https://codereview.chromium.org/61483002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233543 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -256,7 +256,7 @@ class InspectorBackend(object):
     def IsBack():
       return self._browser_backend.tab_list_backend.DoesDebuggerUrlExist(
         self._debugger_url)
-    util.WaitFor(IsBack, 512, 0.5)
+    util.WaitFor(IsBack, 512)
     sys.stderr.write('\n')
     sys.stderr.write('Inspector\'s UI closed. Telemetry will now resume.\n')
     self._Connect()

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

@@ -3,8 +3,7 @@
 # found in the LICENSE file.
 import json
 import logging
-
-from telemetry.core import util
+import time
 
 class InspectorPage(object):
   def __init__(self, inspector_backend):
@@ -30,40 +29,37 @@ class InspectorPage(object):
   def _OnClose(self):
     pass
 
-  def PerformActionAndWaitForNavigate(self, action_function, timeout=60):
-    """Executes action_function, and waits for the navigation to complete.
-
-    action_function is expect to result in a navigation. This function returns
-    when the navigation is complete or when the timeout has been exceeded.
-    """
-
-    # Turn on notifications. We need them to get the Page.frameNavigated event.
+  def _EnablePageNotifications(self, timeout):
     request = {
         'method': 'Page.enable'
         }
     res = self._inspector_backend.SyncRequest(request, timeout)
     assert len(res['result'].keys()) == 0
 
-    def DisablePageNotifications():
-      request = {
-          'method': 'Page.disable'
-          }
-      res = self._inspector_backend.SyncRequest(request, timeout)
-      assert len(res['result'].keys()) == 0
+  def _DisablePageNotifications(self, timeout):
+    request = {
+        'method': 'Page.disable'
+        }
+    res = self._inspector_backend.SyncRequest(request, timeout)
+    assert len(res['result'].keys()) == 0
+
+  def PerformActionAndWaitForNavigate(self, action_function, timeout=60):
+    """Executes action_function, and waits for the navigation to complete.
 
-    self._navigation_pending = True
+    action_function is expect to result in a navigation. This function returns
+    when the navigation is complete or when the timeout has been exceeded.
+    """
+    start_time = time.time()
+    remaining_time = timeout
+    self._EnablePageNotifications(remaining_time)
     try:
       action_function()
-    except:
-      DisablePageNotifications()
-      raise
-
-    def IsNavigationDone(time_left):
-      self._inspector_backend.DispatchNotifications(time_left)
-      return not self._navigation_pending
-    util.WaitFor(IsNavigationDone, timeout, pass_time_left_to_func=True)
-
-    DisablePageNotifications()
+      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)
 
   def Navigate(self, url, script_to_evaluate_on_commit=None, timeout=60):
     """Navigates to |url|.

tools/telemetry/telemetry/core/util.py

@@ -39,7 +39,7 @@ def AddDirToPythonPath(*path_parts):
     sys.path.append(path)
 
 
-def WaitFor(condition, timeout, pass_time_left_to_func=False):
+def WaitFor(condition, timeout):
   """Waits for up to |timeout| secs for the function |condition| to return True.
 
   Polling frequency is (elapsed_time / 10), with a min of .1s and max of 5s.
@@ -50,11 +50,7 @@ def WaitFor(condition, timeout, pass_time_left_to_func=False):
   start_time = time.time()
   while True:
     elapsed_time = time.time() - start_time
-    if pass_time_left_to_func:
-      remaining_time = timeout - elapsed_time
-      res = condition(max(remaining_time, 0.0))
-    else:
-      res = condition()
+    res = condition()
     if res:
       return res
     if elapsed_time > timeout:

tools/telemetry/telemetry/page/html_page_measurement_results_unittest.py

@@ -38,7 +38,7 @@ class StringIOFile(StringIO.StringIO):
 class HtmlPageMeasurementResultsTest(unittest.TestCase):
 
   # TODO(tonyg): Remove this backfill when we can assume python 2.7 everywhere.
-  def assertIn(self, first, second, msg=None):
+  def assertIn(self, first, second, _=None):
     self.assertTrue(first in second,
                     msg="'%s' not found in '%s'" % (first, second))