Move GetChromeVersion and GetChromePid to CrOSInterface.

tools/telemetry/telemetry/core/backends/chrome/cros_interface.py

Index: tools/telemetry/telemetry/core/backends/chrome/cros_interface.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/cros_interface.py b/tools/telemetry/telemetry/core/backends/chrome/cros_interface.py
index edc6f8db86c9d194e1d5b7aaf01ef4809ee184c5..d2f1517e9025ee16d8179daf450d786f768fd6df 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/cros_interface.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/cros_interface.py
@@ -15,6 +15,12 @@ import tempfile
 # around pexpect, I suspect, if we wanted it to be faster. But, this was
 # convenient.
 
+# Some developers' workflow includes running the Chrome process from
+# /usr/local/... instead of the default location. We have to check for both
+# paths in order to support this workflow.
+_CHROME_PATHS = ['/opt/google/chrome/chrome ',
+                '/usr/local/opt/google/chrome/chrome ']
+
 def IsRunningOnCrosDevice():
   """Returns True if we're on a ChromeOS device."""
   lsb_release = '/etc/lsb-release'
@@ -287,6 +293,47 @@ class CrOSInterface(object):
     logging.debug("ListProcesses(<predicate>)->[%i processes]" % len(procs))
     return procs
 
+  def _GetSessionManagerPid(self, procs):
+    """Returns the pid of the session_manager process, given the list of
+    processes."""
+    for pid, process, _, _ in procs:
+      if process.startswith('/sbin/session_manager '):
+        return pid
+    return None
+
+  def GetChromeProcess(self):
+    """Locates the the main chrome browser process.
+
+    Chrome on cros is usually in /opt/google/chrome, but could be in
+    /usr/local/ for developer workflows - debug chrome is too large to fit on
+    rootfs.
+
+    Chrome spawns multiple processes for renderers. pids wrap around after they
+    are exhausted so looking for the smallest pid is not always correct. We
+    locate the session_manager's pid, and look for the chrome process that's an
+    immediate child. This is the main browser process.
+    """
+    procs = self.ListProcesses()
+    session_manager_pid = self._GetSessionManagerPid(procs)
+    if not session_manager_pid:
+      return None
+
+    # Find the chrome process that is the child of the session_manager.
+    for pid, process, ppid, _ in procs:
+      if ppid != session_manager_pid:
+        continue
+      for path in _CHROME_PATHS:
+        if process.startswith(path):
+          return {'pid': pid, 'path': path, 'args': process}
+    return None
+
+  def GetChromePid(self):
+    """Returns pid of main chrome browser process."""
+    result = self.GetChromeProcess()
+    if result and 'pid' in result:
+      return result['pid']
+    return None
+
   def RmRF(self, filename):
     logging.debug("rm -rf %s" % filename)
     self.RunCmdOnDevice(['rm', '-rf', filename], quiet=True)