Make swarming dimensions for GPU bots explicit

scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json

Index: scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json
diff --git a/scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json b/scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json
index 91f687201173bcaf31acd6e6b8e0d5214f05ab2c..a8eafdf4c00919f96ba99ae7cf59e29a12f28eb1 100644
--- a/scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json
+++ b/scripts/slave/recipes/chromium.expected/full_chromium_gpu_Mac_10_10_Retina_Release__AMD_.json
@@ -255,7 +255,7 @@
       "--shards",
       "1",
       "--task-name",
-      "browser_tests/Mac-10.8/ffffffffff/Mac 10.10 Retina Release (AMD)/571",
+      "browser_tests/Mac-10.10/ffffffffff/Mac 10.10 Retina Release (AMD)/571",
       "--dump-json",
       "/path/to/tmp/json",
       "--expiration",
@@ -272,7 +272,7 @@
       "none",
       "--dimension",
       "os",
-      "Mac-10.8",
+      "Mac-10.10",
       "--dimension",
       "pool",
       "Chrome",
@@ -287,7 +287,7 @@
       "--tag",
       "name:browser_tests",
       "--tag",
-      "os:Mac-10.8",
+      "os:Mac-10.10",
       "--tag",
       "project:chromium",
       "--tag",
@@ -297,19 +297,19 @@
       "--tag",
       "slavename:TestSlavename",
       "--tag",
-      "stepname:browser_tests",
+      "stepname:browser_tests on Mac-10.10",
       "--idempotent",
       "ffffffffffffffffffffffffffffffffffffffff",
       "--",
       "--test-launcher-summary-output=${ISOLATED_OUTDIR}/output.json"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "[trigger] browser_tests",
+    "name": "[trigger] browser_tests on Mac-10.10",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"base_task_name\": \"browser_tests/Mac-10.8/ffffffffff/Mac 10.10 Retina Release (AMD)/571\", @@@",
+      "@@@STEP_LOG_LINE@json.output@  \"base_task_name\": \"browser_tests/Mac-10.10/ffffffffff/Mac 10.10 Retina Release (AMD)/571\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"tasks\": {@@@",
-      "@@@STEP_LOG_LINE@json.output@    \"browser_tests/Mac-10.8/ffffffffff/Mac 10.10 Retina Release (AMD)/571\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@    \"browser_tests/Mac-10.10/ffffffffff/Mac 10.10 Retina Release (AMD)/571\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"shard_index\": 0, @@@",
       "@@@STEP_LOG_LINE@json.output@      \"task_id\": \"10000\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"view_url\": \"https://chromium-swarm.appspot.com/user/task/10000\"@@@",
@@ -340,10 +340,10 @@
       "--print-status-updates",
       "--shards",
       "1",
-      "browser_tests/Mac-10.8/ffffffffff/Mac 10.10 Retina Release (AMD)/571"
+      "browser_tests/Mac-10.10/ffffffffff/Mac 10.10 Retina Release (AMD)/571"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "browser_tests",
+    "name": "browser_tests on Mac-10.10",
     "~followup_annotations": [
       "@@@STEP_LINK@shard #0 isolated out@blah@@@"
     ]
@@ -362,14 +362,14 @@
       "--build-number",
       "571",
       "--test-type",
-      "browser_tests",
+      "browser_tests on Mac-10.10",
       "--test-results-server",
       "test-results.appspot.com",
       "--chrome-revision",
       "170242"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "Upload to test-results [browser_tests]"
+    "name": "Upload to test-results [browser_tests on Mac-10.10]"
   },
   {
     "name": "$result",