Add Page. TransferToPageSet

tools/telemetry/telemetry/page/page.py

Index: tools/telemetry/telemetry/page/page.py
diff --git a/tools/telemetry/telemetry/page/page.py b/tools/telemetry/telemetry/page/page.py
index bde3dfb80a63e69daad82ff59c72940b710e9ac8..3af81964a355d65e1648172f92d126d442fbf34b 100644
--- a/tools/telemetry/telemetry/page/page.py
+++ b/tools/telemetry/telemetry/page/page.py
@@ -15,7 +15,7 @@ class Page(object):
     self._url = url
     self._page_set = page_set
     # Default value of base_dir is the directory of the file that defines the
-    # class of this page instace.
+    # class of this page instance.
     if base_dir is None:
       base_dir = os.path.dirname(inspect.getfile(self.__class__))
     self._base_dir = base_dir
@@ -44,6 +44,26 @@ class Page(object):
       if startup_url_scheme == 'file':
         raise ValueError('startup_url with local file scheme is not supported')
 
+  def TransferToPageSet(self, another_page_set):
+    """ Transfer this page to another page set.
+    Args:
+      another_page_set: an instance of telemetry.page.PageSet to transfer this
+          page to.
+    Note:
+      This method removes this page instance from the pages list of its current
+      page_set, so one should be careful not to iterate through the list of
+      pages of a page_set and calling this method.
+      For example, the below loop is erroneous:
+        for p in page_set_A.pages:
+          p.TransferToPageSet(page_set_B.pages)
+    """
+    assert self._page_set
+    if another_page_set is self._page_set:
+      return
+    self._page_set.pages.remove(self)
+    self._page_set = another_page_set
+    self._page_set.AddPage(self)
+
   def RunNavigateSteps(self, action_runner):
     action_runner.NavigateToPage(self)