[Telemetry] Allow telemetry to run without adb root.

Without root the user must manually enable devtools debugging in settings. This
limitation is acceptable as we are able to detect it and instruct the user.

BUG=154415
TEST=Run a telemetry test on a production android image

Review URL: https://codereview.chromium.org/11784007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175353 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/adb_commands.py

@@ -78,6 +78,15 @@ class AdbCommands(object):
     """
     return self._adb.RunShellCommand(command, timeout_time, log_result)
 
+  def CloseApplication(self, package):
+    """Attempt to close down the application, using increasing violence.
+
+    Args:
+      package: Name of the process to kill off, e.g.
+      com.google.android.apps.chrome
+    """
+    self._adb.CloseApplication(package)
+
   def KillAll(self, process):
     """Android version of killall, connected via adb.
 

tools/telemetry/telemetry/android_browser_backend.py

@@ -5,6 +5,7 @@ import json
 import logging
 import os
 import subprocess
+import sys
 import tempfile
 
 from telemetry import adb_commands
@@ -29,7 +30,7 @@ class AndroidBrowserBackend(browser_backend.BrowserBackend):
     self._devtools_remote_port = devtools_remote_port
 
     # Kill old browser.
-    self._adb.KillAll(self._package)
+    self._adb.CloseApplication(self._package)
     self._adb.KillAll('device_forwarder')
     self._adb.Forward('tcp:%d' % self._port, self._devtools_remote_port)
 
@@ -65,7 +66,7 @@ class AndroidBrowserBackend(browser_backend.BrowserBackend):
       self._adb.Push(f.name, cmdline_file)
 
     # Force devtools protocol on, if not already done.
-    if not is_content_shell:
+    if not is_content_shell and self._adb.IsRootEnabled():
       # Make sure we can find the apps' prefs file
       app_data_dir = '/data/data/%s' % self._package
       prefs_file = (app_data_dir +
@@ -110,6 +111,13 @@ class AndroidBrowserBackend(browser_backend.BrowserBackend):
     try:
       self._WaitForBrowserToComeUp()
       self._PostBrowserStartupInitialization()
+    except browser_gone_exception.BrowserGoneException:
+      logging.critical('Failed to connect to browser.')
+      if not self._adb.IsRootEnabled():
+        logging.critical(
+          'Ensure web debugging is enabled in Chrome at '
+          '"Settings > Developer tools > Enable USB Web debugging".')
+      sys.exit(1)
     except:
       import traceback
       traceback.print_exc()
@@ -128,7 +136,7 @@ class AndroidBrowserBackend(browser_backend.BrowserBackend):
     super(AndroidBrowserBackend, self).Close()
 
     self._adb.RunShellCommand('rm %s' % self._cmdline_file)
-    self._adb.KillAll(self._package)
+    self._adb.CloseApplication(self._package)
 
   def IsBrowserRunning(self):
     pids = self._adb.ExtractPid(self._package)

tools/telemetry/telemetry/android_browser_finder.py

@@ -103,12 +103,6 @@ def FindAllAvailableBrowsers(options, logging=real_logging):
 
   adb = adb_commands.AdbCommands(device=device)
 
-  # See if adb is root
-  if not adb.IsRootEnabled():
-    logging.warn('ADB is not root. Please make it root by doing:')
-    logging.warn(' adb root')
-    return []
-
   packages = adb.RunShellCommand('pm list packages')
   possible_browsers = []
   if 'package:' + CONTENT_SHELL_PACKAGE in packages: