Revert of 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 fd775e3eb88624d5f32f1c58202564db91a94436..799df13fb5cca50deec558e84dcfa8e9ddfc79e2 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -343,6 +343,12 @@
           "can_use_on_swarming_builders": true
         },
         "test": "app_shell_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "ash_unittests"
       },
       {
         "swarming": {
@@ -734,6 +740,7 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
+      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",
@@ -806,6 +813,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "ash_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "aura_unittests"
       },
       {
@@ -1196,6 +1209,12 @@
           "can_use_on_swarming_builders": true
         },
         "test": "app_shell_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "ash_unittests"
       },
       {
         "swarming": {
@@ -1540,6 +1559,7 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
+      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",
@@ -1650,6 +1670,7 @@
       "accessibility_unittests",
       "app_list_unittests",
       "app_shell_unittests",
+      "ash_unittests",
       "aura_unittests",
       "cacheinvalidation_unittests",
       "cast_unittests",