Delete chromium valgrind bots.

masters/master.tryserver.chromium.linux/master.cfg

Index: masters/master.tryserver.chromium.linux/master.cfg
diff --git a/masters/master.tryserver.chromium.linux/master.cfg b/masters/master.tryserver.chromium.linux/master.cfg
index b46c5f205bdcd1ec0c6758b91eacccb78f811e39..01fba438b91099ec3939ef1ef1357abf75c0cb9f 100644
--- a/masters/master.tryserver.chromium.linux/master.cfg
+++ b/masters/master.tryserver.chromium.linux/master.cfg
@@ -244,13 +244,6 @@ b_linux_site_isolation = {
   'slavebuilddir': 'linux',
 }
 
-b_linux_valgrind = {
-  'name': 'linux_valgrind',
-  'factory': m_annotator.BaseFactory('chromium_trybot'),
-  # Share build directory with compatible existing builders to save space.
-  'slavebuilddir': 'linux',
-}
-
 b_linux_chromium_asan_rel_ng = {
   'name': 'linux_chromium_asan_rel_ng',
   'factory': m_annotator.BaseFactory(
@@ -416,7 +409,6 @@ c['builders'] = [
   b_linux_nacl_sdk,
   b_linux_nacl_sdk_build,
   b_linux_site_isolation,
-  b_linux_valgrind,
 ] + chromium_builders + ozone_builders + variable_builders