[Telemetry] Fix Octane on non-rooted devices.

This condition was added to prevent the zlib benchmark from OOMing on the
Galaxy Nexus device. Now, it's no longer on the waterfall, so I'm just
removing the check.

This has the desired side-effect that we'll try to run this benchmark on any
device, even if we can't determine the physical memory.

BUG=391079

Review URL: https://codereview.chromium.org/450873002

Cr-Commit-Position: refs/heads/master@{#288486}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288486 0039d316-1c4b-4281-b951-d872f2087c98

tools/perf/benchmarks/octane.py

@@ -76,7 +76,9 @@ class _OctaneMeasurement(page_measurement.PageMeasurement):
     self._power_metric = power.PowerMetric(browser)
 
   def WillNavigateToPage(self, page, tab):
-    if tab.browser.memory_stats['SystemTotalPhysicalMemory'] < 1 * _GB:
+    memory_stats = tab.browser.memory_stats
+    if ('SystemTotalPhysicalMemory' in memory_stats and
+        memory_stats['SystemTotalPhysicalMemory'] < 1 * _GB):
       skipBenchmarks = '"zlib"'
     else:
       skipBenchmarks = ''