Added src-side JSON file for GPU FYI bots running Chromium recipe.

This currently describes just the building and running of the WebGL
conformance tests on the new Linux and Mac Release and Debug builders
and testers. Once this is working, the other tests will be added.

BUG=542370

Review URL: https://codereview.chromium.org/1547383002

Cr-Commit-Position: refs/heads/master@{#367099}

testing/buildbot/chromium.gpu.fyi.json

+{
+  "GPU NextGen Linux Builder": {},
+  "GPU NextGen Linux Builder (dbg)": {},
+  "GPU NextGen Mac Builder": {},
+  "GPU NextGen Mac Builder (dbg)": {},
+  "Linux NextGen Debug (NVIDIA)": {
+    "isolated_scripts": [
+      {
+        "args": [
+          "webgl_conformance",
+          "--show-stdout",
+          "--browser=debug",
+          "-v",
+          "--extra-browser-args=\"--enable-logging=stderr --js-flags=--expose-gc\""
+        ],
+        "isolate_name": "telemetry_gpu_test",
+        "name": "webgl_conformance",
+        "override_compile_targets": [
+          "telemetry_gpu_test_run"
+        ],
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "10de:104a",
+              "os": "Linux"
+            }
+          ]
+        }
+      }
+    ]
+  },
+  "Linux NextGen Release (NVIDIA)": {
+    "isolated_scripts": [
+      {
+        "args": [
+          "webgl_conformance",
+          "--show-stdout",
+          "--browser=release",
+          "-v",
+          "--extra-browser-args=\"--enable-logging=stderr --js-flags=--expose-gc\""
+        ],
+        "isolate_name": "telemetry_gpu_test",
+        "name": "webgl_conformance",
+        "override_compile_targets": [
+          "telemetry_gpu_test_run"
+        ],
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "10de:104a",
+              "os": "Linux"
+            }
+          ]
+        }
+      }
+    ]
+  },
+  "Mac NextGen 10.10 Retina Debug (AMD)": {
+    "isolated_scripts": [
+      {
+        "args": [
+          "webgl_conformance",
+          "--show-stdout",
+          "--browser=debug",
+          "-v",
+          "--extra-browser-args=\"--enable-logging=stderr --js-flags=--expose-gc\""
+        ],
+        "isolate_name": "telemetry_gpu_test",
+        "name": "webgl_conformance",
+        "override_compile_targets": [
+          "telemetry_gpu_test_run"
+        ],
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "1002:6821",
+              "hidpi": "1",
+              "os": "Mac-10.10"
+            }
+          ]
+        }
+      }
+    ]
+  },
+  "Mac NextGen 10.10 Retina Release (AMD)": {
+    "isolated_scripts": [
+      {
+        "args": [
+          "webgl_conformance",
+          "--show-stdout",
+          "--browser=release",
+          "-v",
+          "--extra-browser-args=\"--enable-logging=stderr --js-flags=--expose-gc\""
+        ],
+        "isolate_name": "telemetry_gpu_test",
+        "name": "webgl_conformance",
+        "override_compile_targets": [
+          "telemetry_gpu_test_run"
+        ],
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "gpu": "1002:6821",
+              "hidpi": "1",
+              "os": "Mac-10.10"
+            }
+          ]
+        }
+      }
+    ]
+  }
+}