Test dEQP GLES3 on ANGLE's Metal backend

The Metal backend is mostly GLES3 conformant. We should enable testing
on the bots.

Bug: angleproject:2634
Bug: angleproject:4235
Change-Id: Ibb251ebc2545edd405de0d4a7641bbfdad010ee0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2508293Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Cr-Commit-Position: refs/heads/master@{#822750}

testing/buildbot/chromium.gpu.fyi.json

@@ -20961,6 +20961,34 @@
         "test": "angle_deqp_gles3_tests",
         "test_id_prefix": "ninja://third_party/angle/src/tests:angle_deqp_gles3_tests/",
         "use_isolated_scripts_api": true
+      },
+      {
+        "args": [
+          "angle_deqp_gles3_tests",
+          "--use-angle=metal",
+          "--bot-mode"
+        ],
+        "merge": {
+          "args": [],
+          "script": "//testing/merge_scripts/standard_isolated_script_merge.py"
+        },
+        "name": "angle_deqp_gles3_metal_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "containment_type": "AUTO",
+          "dimension_sets": [
+            {
+              "gpu": "1002:6821",
+              "hidpi": "1",
+              "os": "Mac-10.14.6",
+              "pool": "chromium.tests.gpu"
+            }
+          ],
+          "service_account": "chromium-tester@chops-service-accounts.iam.gserviceaccount.com"
+        },
+        "test": "angle_deqp_gles3_tests",
+        "test_id_prefix": "ninja://third_party/angle/src/tests:angle_deqp_gles3_tests/",
+        "use_isolated_scripts_api": true
       }
     ]
   },
@@ -21097,6 +21125,32 @@
         "test": "angle_deqp_gles3_tests",
         "test_id_prefix": "ninja://third_party/angle/src/tests:angle_deqp_gles3_tests/",
         "use_isolated_scripts_api": true
+      },
+      {
+        "args": [
+          "angle_deqp_gles3_tests",
+          "--use-angle=metal",
+          "--bot-mode"
+        ],
+        "merge": {
+          "args": [],
+          "script": "//testing/merge_scripts/standard_isolated_script_merge.py"
+        },
+        "name": "angle_deqp_gles3_metal_tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "containment_type": "AUTO",
+          "dimension_sets": [
+            {
+              "gpu": "8086:0a2e",
+              "os": "Mac-10.15.5"
+            }
+          ],
+          "service_account": "chromium-tester@chops-service-accounts.iam.gserviceaccount.com"
+        },
+        "test": "angle_deqp_gles3_tests",
+        "test_id_prefix": "ninja://third_party/angle/src/tests:angle_deqp_gles3_tests/",
+        "use_isolated_scripts_api": true
       }
     ]
   },

testing/buildbot/test_suites.pyl

@@ -1872,6 +1872,20 @@
       },
     },
 
+    'gpu_angle_deqp_gles3_metal_gtests': {
+      'angle_deqp_gles3_metal_tests': {
+        'args': [
+          'angle_deqp_gles3_tests',
+          '--use-angle=metal',
+        ],
+        'desktop_args': [
+          '--bot-mode',
+        ],
+        'test': 'angle_deqp_gles3_tests',
+        'use_isolated_scripts_api': True,
+      },
+    },
+
     'gpu_angle_deqp_gles3_vulkan_gtests': {
       'angle_deqp_gles3_vulkan_tests': {
         'args': [
@@ -5021,6 +5035,7 @@
       'gpu_angle_deqp_gles2_gl_gtests',
       'gpu_angle_deqp_gles2_metal_gtests',
       'gpu_angle_deqp_gles3_gl_gtests',
+      'gpu_angle_deqp_gles3_metal_gtests',
     ],
 
     'gpu_angle_deqp_win7_nvidia_gtests': [