Added Tab.SnapshotContent and MapsGL example to telemetry

tools/telemetry/telemetry/inspector_page_unittest.py

Index: tools/telemetry/telemetry/inspector_page_unittest.py
diff --git a/tools/telemetry/telemetry/inspector_page_unittest.py b/tools/telemetry/telemetry/inspector_page_unittest.py
index 8bb9b99f730acd5df9e485cabc0cc27cba94cc74..1d214ab5c6455b71871db55bf85dc21837aeb7f4 100644
--- a/tools/telemetry/telemetry/inspector_page_unittest.py
+++ b/tools/telemetry/telemetry/inspector_page_unittest.py
@@ -43,3 +43,24 @@ class InspectorPageTest(tab_test_case.TabTestCase):
     self.assertTrue(custom_action_called[0])
     self.assertEquals(self._tab.runtime.Evaluate('document.location.pathname;'),
                       '/blank.html')
+
+class GpuInspectorPageTest(tab_test_case.TabTestCase):
+  def setUp(self):
+    self._extra_browser_args = ['--enable-gpu-benchmarking']
+    super(GpuInspectorPageTest, self).setUp()
+
+  def testScreenshot(self):
+    unittest_data_dir = os.path.join(os.path.dirname(__file__),
+                                     '..', 'unittest_data')
+    self._browser.SetHTTPServerDirectory(unittest_data_dir)
+    self._tab.page.Navigate(
+      self._browser.http_server.UrlOf('green_rect.html'))
+    self._tab.WaitForDocumentReadyStateToBeComplete()
+
+    # Skip this test if running against a browser without screenshot support
+    if self._tab.page.screenshot_supported:
+      screenshot = self._tab.page.Screenshot(5)
+      assert screenshot
+      screenshot.GetPixelColor(0, 0).AssertIsRGB(0, 255, 0)
+      screenshot.GetPixelColor(31, 31).AssertIsRGB(0, 255, 0)
+      screenshot.GetPixelColor(32, 32).AssertIsRGB(255, 255, 255)