Swarm debug Windows 7 tests on main waterfall.

testing/buildbot/chromium.win.json

 {
   "XP Tests (1)": {
     "gtest_tests": [
       "interactive_ui_tests",
       "cacheinvalidation_unittests",
       "cast_unittests",
       "cc_unittests",
       "chromedriver_unittests",
       "courgette_unittests",
       "crypto_unittests",
@@ skipping 317 matching lines @@
     "gtest_tests": [
     ]
   },
   "Win 7 Tests x64 (3)": {
     "gtest_tests": [
     ]
   },
   "Win7 Tests (dbg)(1)": {
     "gtest_tests": [
       "accessibility_unittests",
-      "base_unittests",
+      {
+        "test": "ash_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      "aura_unittests",
+      {
+        "test": "base_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      {
+        "test": "browser_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 20
+        }
+      },
       "cacheinvalidation_unittests",
       "cast_unittests",
       "cc_unittests",
       "chromedriver_unittests",
       "chrome_elf_unittests",
       "components_unittests",
+      "compositor_unittests",
+      {
+        "test": "content_browsertests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 2
+        }
+      },
+      {
+        "test": "content_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
       "courgette_unittests",
       "crypto_unittests",
+      "events_unittests",
       "extensions_unittests",
       "gcm_unit_tests",
       "gpu_unittests",
-      "url_unittests",
+      "installer_util_unittests",
+      {
+        "test": "interactive_ui_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 4
+        }
+      },
+      "ipc_tests",
       "jingle_unittests",
       "media_unittests",
-      "ppapi_unittests",
-      "printing_unittests",
-      "remoting_unittests",
-      "aura_unittests",
-      "ash_unittests",
-      "compositor_unittests",
-      "events_unittests",
-      "ipc_tests",
-      "sync_integration_tests",
-      "sync_unit_tests",
-      "unit_tests",
-      "sql_unittests",
-      "ui_unittests",
-      "content_unittests",
-      "views_unittests",
-      "wm_unittests",
-      "installer_util_unittests"
-    ]
-  },
-  "Win7 Tests (dbg)(2)": {
-    "gtest_tests": [
-      "net_unittests",
-      {"test": "browser_tests", "shard_index": 0, "total_shards": 5},
-      "content_browsertests"
-    ]
-  },
-  "Win7 Tests (dbg)(3)": {
-    "gtest_tests": [
-      "sbox_unittests",
-      "sbox_integration_tests",
-      "sbox_validation_tests",
-      {"test": "browser_tests", "shard_index": 1, "total_shards": 5}
-     ]
-  },
-  "Win7 Tests (dbg)(4)": {
-    "gtest_tests": [
       "mojo_apps_js_unittests",
       "mojo_common_unittests",
       "mojo_js_unittests",
       "mojo_public_bindings_unittests",
       "mojo_public_environment_unittests",
       "mojo_public_system_unittests",
       "mojo_public_utility_unittests",
       "mojo_system_unittests",
-      {"test": "browser_tests", "shard_index": 2, "total_shards": 5}
+      {
+        "test": "net_unittests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      "ppapi_unittests",
+      "printing_unittests",
+      "remoting_unittests",
+      "sbox_unittests",
+      "sbox_integration_tests",
+      "sbox_validation_tests",
+      "sql_unittests",
+      {
+        "test": "sync_integration_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 2
+        }
+      },
+      "sync_unit_tests",
+      "ui_unittests",
+      {
+        "test": "unit_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        }
+      },
+      "url_unittests",
+      "views_unittests",
+      "wm_unittests"
+    ]
+  },
+  "Win7 Tests (dbg)(2)": {
+    "gtest_tests": [
+    ]
+  },
+  "Win7 Tests (dbg)(3)": {
+    "gtest_tests": [
+     ]
+  },
+  "Win7 Tests (dbg)(4)": {
+    "gtest_tests": [
     ]
   },
   "Win7 Tests (dbg)(5)": {
     "gtest_tests": [
-      {"test": "browser_tests", "shard_index": 3, "total_shards": 5}
     ]
   },
   "Win7 Tests (dbg)(6)": {
     "gtest_tests": [
-      {"test": "browser_tests", "shard_index": 4, "total_shards": 5}
     ]
   },
   "Interactive Tests (dbg)": {
     "gtest_tests": [
-      "interactive_ui_tests"
     ]
   },
   "Win8 Aura": {
     "gtest_tests": [
       "views_unittests",
       "wm_unittests",
       "aura_unittests",
       "ash_unittests",
       "compositor_unittests",
       "content_browsertests",
       "events_unittests"
     ]
   }
 }