Upstream: Test scripts for Android (phase 2)

build/android/flag_changer.py

Index: build/android/flag_changer.py
diff --git a/build/android/flag_changer.py b/build/android/flag_changer.py
new file mode 100644
index 0000000000000000000000000000000000000000..636022b9abd80b6a21b2d702b1a53fea956cb5c6
--- /dev/null
+++ b/build/android/flag_changer.py
@@ -0,0 +1,50 @@
+#!/usr/bin/python
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+# Location where chrome reads command line flags from
+CHROME_COMMAND_FILE = '/data/local/chrome-command-line'
+
+
+class FlagChanger(object):
+  """Temporarily changes the flags Chrome runs with."""
+
+  def __init__(self, android_cmd):
+    self._android_cmd = android_cmd
+    self._old_flags = None
+
+  def Set(self, flags, append=False):
+    """Sets the command line flags used when chrome is started.
+
+    Args:
+      flags: A list of flags to set, eg. ['--single-process'].
+      append: Whether to append to existing flags or overwrite them.
+    """
+    if flags:
+      assert flags[0] != 'chrome'
+
+    if not self._old_flags:
+      self._old_flags = self._android_cmd.GetFileContents(CHROME_COMMAND_FILE)
+      if self._old_flags:
+        self._old_flags = self._old_flags[0].strip()
+
+    if append and self._old_flags:
+      # Avoid appending flags that are already present.
+      new_flags = filter(lambda flag: self._old_flags.find(flag) == -1, flags)
+      self._android_cmd.SetFileContents(CHROME_COMMAND_FILE,
+                                        self._old_flags + ' ' +
+                                        ' '.join(new_flags))
+    else:
+      self._android_cmd.SetFileContents(CHROME_COMMAND_FILE,
+                                        'chrome ' + ' '.join(flags))
+
+  def Restore(self):
+    """Restores the flags to their original state."""
+    if self._old_flags == None:
+      return  # Set() was never called.
+    elif self._old_flags:
+      self._android_cmd.SetFileContents(CHROME_COMMAND_FILE, self._old_flags)
+    else:
+      self._android_cmd.RunShellCommand('rm ' + CHROME_COMMAND_FILE)