Add performance_browser_tests to some Mac bots

testing/buildbot/chromium.perf.json

Index: testing/buildbot/chromium.perf.json
diff --git a/testing/buildbot/chromium.perf.json b/testing/buildbot/chromium.perf.json
index 3f311cb2a3943ce1a5d7f2f894ea2d1c2fc655c8..f729aaca0822a376ee16da15b4a64a6015e3a6c0 100644
--- a/testing/buildbot/chromium.perf.json
+++ b/testing/buildbot/chromium.perf.json
@@ -27404,6 +27404,26 @@
         }
       },
       {
+        "args": [],
+        "isolate_name": "performance_browser_tests",
+        "name": "performance_browser_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "8086:1626",
+              "id": "build126-b1",
+              "os": "Mac-10.11",
+              "pool": "Chrome-perf"
+            }
+          ],
+          "expiration": 36000,
+          "hard_timeout": 7200,
+          "ignore_task_failure": false,
+          "io_timeout": 3600
+        }
+      },
+      {
         "args": [
           "power.idle_platform",
           "-v",
@@ -39742,6 +39762,26 @@
         }
       },
       {
+        "args": [],
+        "isolate_name": "performance_browser_tests",
+        "name": "performance_browser_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "1002:6821",
+              "id": "build132-b1",
+              "os": "Mac-10.11",
+              "pool": "Chrome-perf"
+            }
+          ],
+          "expiration": 36000,
+          "hard_timeout": 7200,
+          "ignore_task_failure": false,
+          "io_timeout": 3600
+        }
+      },
+      {
         "args": [
           "power.idle_platform",
           "-v",
@@ -45911,6 +45951,26 @@
         }
       },
       {
+        "args": [],
+        "isolate_name": "performance_browser_tests",
+        "name": "performance_browser_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "8086:0d26",
+              "id": "build8-b1",
+              "os": "Mac-10.11",
+              "pool": "Chrome-perf"
+            }
+          ],
+          "expiration": 36000,
+          "hard_timeout": 7200,
+          "ignore_task_failure": false,
+          "io_timeout": 3600
+        }
+      },
+      {
         "args": [
           "power.idle_platform",
           "-v",