Add perf tests for starting Chrome with URL

tools/telemetry/telemetry/page/page_test.py

Index: tools/telemetry/telemetry/page/page_test.py
diff --git a/tools/telemetry/telemetry/page/page_test.py b/tools/telemetry/telemetry/page/page_test.py
index 368aa894706c1fb48d66ebe8a54bbd8ada56cebc..d1100db1a3c51c0a7fab16ae16837295f38ed51f 100644
--- a/tools/telemetry/telemetry/page/page_test.py
+++ b/tools/telemetry/telemetry/page/page_test.py
@@ -107,10 +107,28 @@ class PageTest(object):
   def close_tabs_before_run(self, close_tabs):
     self._close_tabs_before_run = close_tabs
 
-  def NeedsBrowserRestartAfterEachRun(self, browser):  # pylint: disable=W0613
-    """Override to specify browser restart after each run."""
+  def AlwaysRestartBrowserForEachPage(self):

[jeremy, 2013/12/17 11:29:44]

Any reason not to name this: RestartBrowserForEachPage() ?

[aberent, 2013/12/17 17:31:27]

Done.

+    """ Should the browser be restarted for each page?
+
+    This returns true if the test needs to unconditionally restart the
+    browser for each page. It may be called before the browser is started.
+
+    This must return the same result every time it is called within a single
+    run of a page set.
+    """
     return self._needs_browser_restart_after_each_run
 
+  def NeedsBrowserRestartBeforeNextPage(self, browser):  # pylint: disable=W0613

[jeremy, 2013/12/17 11:29:44]

nit: rename to RestartBrowserBeforeNextPage() ?

[aberent, 2013/12/17 17:31:27]

Done.

+    """Should be restarted before the next page?
+
+    This is called after a page is run to decide whether the browser needs to
+    be restarted. A test that wants to check the state of the browser before
+    deciding whether to restart the browser should override this.
+
+    This may return a different result each time it is called.
+    """
+    return self.AlwaysRestartBrowserForEachPage()
+
   def AddCommandLineOptions(self, parser):
     """Override to expose command-line options for this test.
 
@@ -124,7 +142,15 @@ class PageTest(object):
     pass
 
   def CustomizeBrowserOptionsForPage(self, page, options):
-    """Add options specific to the test and the given page."""
+    """Add options specific to the test and the given page.
+
+    This will be used differently depending on the value returned by
+    AlwaysRestartBrowserBeforeEachPage. If that function returns True then this
+    this function will be called for each page individually before the browser

[jeremy, 2013/12/17 11:29:44]

nit:this this

+    is started for that page. If it returns False then this function will be
+    called for every page in the page set before the browser is started for any
+    page.
+    """
     if not self.CanRunForPage(page):
       return
     interactive = options and options.interactive