Revert of Removing browser.Start() and instead starts the browser at the point of creation.

tools/telemetry/telemetry/core/possible_browser.py

Index: tools/telemetry/telemetry/core/possible_browser.py
diff --git a/tools/telemetry/telemetry/core/possible_browser.py b/tools/telemetry/telemetry/core/possible_browser.py
index db9f7ac6e4fbf783009a7be305b5d149c41c05e0..204b1f860c0f6c52aa51c4936ffafa7f2d89eb5b 100644
--- a/tools/telemetry/telemetry/core/possible_browser.py
+++ b/tools/telemetry/telemetry/core/possible_browser.py
@@ -18,10 +18,6 @@
     self._supports_tab_control = supports_tab_control
     self._platform = None
     self._platform_backend = None
-    self._archive_path = None
-    self._append_to_existing_wpr = False
-    self._make_javascript_deterministic = True
-    self._credentials_path = None
 
   def __repr__(self):
     return 'PossibleBrowser(browser_type=%s)' % self.browser_type
@@ -69,12 +65,3 @@
 
   def last_modification_time(self):
     return -1
-
-  def SetReplayArchivePath(self, archive_path, append_to_existing_wpr,
-                           make_javascript_deterministic):
-    self._archive_path = archive_path
-    self._append_to_existing_wpr = append_to_existing_wpr
-    self._make_javascript_deterministic = make_javascript_deterministic
-
-  def SetCredentialsPath(self, credentials_path):
-    self._credentials_path = credentials_path