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

tools/telemetry/telemetry/browser_backend.py

Index: tools/telemetry/telemetry/browser_backend.py
diff --git a/tools/telemetry/telemetry/browser_backend.py b/tools/telemetry/telemetry/browser_backend.py
index 5ec3205a2ddabe26a906d69780c359c664f251e1..8beb268c2d5fcefeb13eff29dcd3119a9f3bf83d 100644
--- a/tools/telemetry/telemetry/browser_backend.py
+++ b/tools/telemetry/telemetry/browser_backend.py
@@ -8,6 +8,7 @@ import json
 import re
 
 from telemetry import browser_gone_exception
+from telemetry import extension_page
 from telemetry import inspector_backend
 from telemetry import tab
 from telemetry import user_agent
@@ -87,6 +88,18 @@ class BrowserBackend(object):
     req = urllib2.urlopen(url, timeout=timeout)
     return req.read()
 
+  def _ListExtensionPages(self, extension_id, timeout=None):
+    try:
+      data = self._Request('', timeout=timeout)
+      all_contexts = json.loads(data)
+      pages = [ctx for ctx in all_contexts
+               if ctx['url'].startswith('chrome-extension://%s' % extension_id)]
+      return pages
+    except (socket.error, httplib.BadStatusLine, urllib2.URLError):
+      if not self.IsBrowserRunning():
+        raise browser_gone_exception.BrowserGoneException()
+      raise BrowserConnectionGoneException()
+
   def _ListTabs(self, timeout=None):
     try:
       data = self._Request('', timeout=timeout)
@@ -104,6 +117,13 @@ class BrowserBackend(object):
         raise browser_gone_exception.BrowserGoneException()
       raise BrowserConnectionGoneException()
 
+  def _GetTabByUrl(self, url):
+    for target in self._ListTabs():
+      if target['url'] == url:
+        return target
+
+    return None
+
   def NewTab(self, timeout=None):
     data = self._Request('new', timeout=timeout)
     new_tab = json.loads(data)
@@ -126,10 +146,26 @@ class BrowserBackend(object):
   def GetNthTabUrl(self, index):
     return self._ListTabs()[index]['url']
 
+  def ConnectToExtensionPage(self, browser, extension_id):
+    page = self._ListExtensionPages(extension_id)[0]
+    if page is None:
+      return None
+
+    ib = inspector_backend.InspectorBackend(self, page)
+    return extension_page.ExtensionPage(tab.Tab(browser, ib))
+
   def ConnectToNthTab(self, browser, index):
     ib = inspector_backend.InspectorBackend(self, self._ListTabs()[index])
     return tab.Tab(browser, ib)
 
+  def ConnectToPageByUrl(self, browser, url):
+    selected_page = self._GetTabByUrl(url)
+    if selected_page is None:
+      return None
+
+    ib = inspector_backend.InspectorBackend(self, selected_page)
+    return tab.Tab(browser, ib)
+
   def DoesDebuggerUrlExist(self, url):
     matches = [t for t in self._ListTabs()
                if 'webSocketDebuggerUrl' in t and\