Remove remote tree host and some related input and metro_driver code

testing/buildbot/chromium.win.json

Index: testing/buildbot/chromium.win.json
diff --git a/testing/buildbot/chromium.win.json b/testing/buildbot/chromium.win.json
index 799df13fb5cca50deec558e84dcfa8e9ddfc79e2..fd775e3eb88624d5f32f1c58202564db91a94436 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -348,12 +348,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "ash_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "aura_unittests"
       },
       {
@@ -740,7 +734,6 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
-      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",
@@ -813,12 +806,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "ash_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "aura_unittests"
       },
       {
@@ -1214,12 +1201,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "ash_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "aura_unittests"
       },
       {
@@ -1559,7 +1540,6 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
-      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",
@@ -1670,7 +1650,6 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
-      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",