Added Tab.SnapshotContent and MapsGL example to telemetry

tools/telemetry/examples/gpu_mapsgl_endurance_browsertest.py

Index: tools/telemetry/examples/gpu_mapsgl_endurance_browsertest.py
diff --git a/tools/telemetry/examples/gpu_mapsgl_endurance_browsertest.py b/tools/telemetry/examples/gpu_mapsgl_endurance_browsertest.py
new file mode 100755
index 0000000000000000000000000000000000000000..2e3af398b9b03fee80c549142d2c4c17f458778b
--- /dev/null
+++ b/tools/telemetry/examples/gpu_mapsgl_endurance_browsertest.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 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.
+import os
+import sys
+import time
+import json
+
+sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
+import telemetry
+
+def ReadTestExpectations(json_test_expectations_path):
+  f = open(json_test_expectations_path, 'r')
+  json_contents = json.load(f)
+  return json_contents
+
+def CompareToExpectedResults(snapshot, expectations):
+  result = True
+  for expectation in expectations:
+    location = expectation["location"]
+    iter_result = snapshot.CheckPixelColor(location[0], location[1],
+        expectation["color"], expectation["tolerance"])
+    if not iter_result:
+      print("FAILURE: Expected", location, "to be", expectation["color"],
+          "but got", snapshot.GetPixel(location[0], location[1]))
+    result &= iter_result
+  return result
+
+def RunSingleTest(browser,
+                  url,
+                  json_test_expectations_filename,
+                  failure_filename_prefix):
+  expectations = ReadTestExpectations(json_test_expectations_filename)
+
+  #TODO: BringBrowserWindowToFront?

[Ken Russell (switch to Gerrit), 2012/11/09 20:26:28]

TODOs require a contact person.
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#TODO_Comments

+  #TODO: browser.window.SetBounds?
+
+  with browser.ConnectToNthTab(0) as tab:
+    tab.page.Navigate(url)
+    time.sleep(2) # Why is this needed?
+    tab.WaitForDocumentReadyStateToBeComplete()
+
+    if tab.runtime.Evaluate('window.chrome.gpuBenchmarking === undefined'):
+      print 'Browser does not support gpu benchmarks API.'
+      return 255
+
+    if tab.runtime.Evaluate(
+        'window.chrome.gpuBenchmarking.windowSnapshot === undefined'):
+      print 'Browser does not support window snapshot API.'
+      return 255
+
+    # Mock up the message queue functionality used by the mapping test

[Ken Russell (switch to Gerrit), 2012/11/09 20:26:28]

Please use periods after comments. It makes them easier to read.

+    tab.runtime.Evaluate("""
+      if(!window.domAutomationController) {
+        window.domAutomationController = {};
+      }
+      window.domAutomationController.message_queue = [];
+      window.domAutomationController.setAutomationId = function(id) {}
+      window.domAutomationController.send = function(val) {
+        window.domAutomationController.message_queue.push(val);
+      }
+    """)
+
+    def CheckMessages():
+      message = tab.runtime.Evaluate(
+          "window.domAutomationController.message_queue.shift();")
+      return message == "FINISHED"
+
+    telemetry.WaitFor(CheckMessages, 1000, 0.5)
+
+    snapshot = tab.SnapshotContent()
+    if not snapshot:
+      print "Failed to capture snapshot"
+      return 255
+
+    all_pixels_match = CompareToExpectedResults(snapshot, expectations)
+
+    if not all_pixels_match:
+      print "Color check failed at end of test"
+      snapshot.WriteFile(failure_filename_prefix + "-output.png")
+      return 1
+
+    return 0
+
+def Main(args):
+  options = telemetry.BrowserOptions()
+  parser = options.CreateParser('snapshot_test.py')
+  options, args = parser.parse_args(args)
+
+  options.extra_browser_args.append('--enable-gpu-benchmarking')
+  browser_to_create = telemetry.FindBrowser(options)
+  assert browser_to_create
+  with browser_to_create.Create() as browser:
+    return RunSingleTest(browser,
+                "http://localhost:8000/basic.html",
+                "mapsgl_single_run_basic_expectations.json",
+                "single-run-basic")
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))