Proof of concept for running extension API stack through dev tools.

tools/telemetry/telemetry/possible_browser.py

Index: tools/telemetry/telemetry/possible_browser.py
diff --git a/tools/telemetry/telemetry/possible_browser.py b/tools/telemetry/telemetry/possible_browser.py
index 2cb995fea58d416c5002418779a72578260c501b..63a65ec69206692505c7dcd91d8b7cf327dd6d43 100644
--- a/tools/telemetry/telemetry/possible_browser.py
+++ b/tools/telemetry/telemetry/possible_browser.py
@@ -7,9 +7,10 @@ class PossibleBrowser(object):
   Call Create() to launch the browser and begin manipulating it..
   """
 
-  def __init__(self, browser_type, options):
+  def __init__(self, browser_type, options, supports_extensions):
     self.browser_type = browser_type
     self._options = options
+    self._supports_extensions = supports_extensions
 
   def __repr__(self):
     return 'PossibleBrowser(browser_type=%s)' % self.browser_type
@@ -18,5 +19,9 @@ class PossibleBrowser(object):
   def options(self):
     return self._options
 
+  @property
+  def supports_extensions(self):
+    return self._supports_extensions
+
   def Create(self):
     raise NotImplementedError()