Configure GitHub Actions workflows to use merge queue

Add support for the `merge_group` event trigger in the main Cobalt CI
workflows (`main.yaml` and its callers: `aosp.yaml`, `linux.yaml`,
`evergreen.yaml`, `tvos.yaml`, `raspi-2-modular.yaml`, `android.yaml`)
and the `lint.yaml` workflow.

Specifically:
- Enable Docker image caching on `merge_group` events in `main.yaml`.
- Set fetch depth to 2 for checkout on `merge_group` in `main.yaml` and `lint.yaml`.
- Skip `check-bug-id` job in `lint.yaml` for `merge_group` events to avoid failures due to missing pull request context.
- Restrict the `merge_group` trigger to the `main` branch across all workflows.

TAG=agy
CONV=3d0914e4-a97d-4965-b79b-db24090b185b

Author: oxve

.github/workflows/android.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly:

.github/workflows/aosp.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly:

.github/workflows/evergreen.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly:

.github/workflows/lint.yaml

@@ -10,6 +10,9 @@ on:
     branches:
       - main
       - feature/*
+  merge_group:
+    branches:
+      - main
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event_name }} @ ${{ github.event.label.name || github.event.pull_request.number || github.sha }} @ ${{ github.event.label.name && github.event.pull_request.number || github.event.action }}
@@ -54,6 +57,7 @@ jobs:
           pre-commit run --show-diff-on-failure --color=always --from-ref HEAD~1 --to-ref HEAD
   check-bug-id:
     name: Bug ID Check
+    if: github.event_name != 'merge_group'
     runs-on: ubuntu-latest
     steps:
       - name: Bug ID Check

.github/workflows/linux.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly:

.github/workflows/main.yaml

@@ -340,7 +340,7 @@ jobs:
         uses: ./.github/actions/docker
         with:
           docker_service: ${{ needs.initialize.outputs.docker_service }}
-          is_pr: ${{ (github.event_name == 'pull_request') }}
+          is_pr: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
           docker_content_sha: ${{ needs.initialize.outputs.docker_content_sha }}
           github_token: ${{ secrets.GITHUB_TOKEN }}
     outputs:
@@ -363,7 +363,7 @@ jobs:
         uses: ./.github/actions/docker
         with:
           docker_service: unittest
-          is_pr: ${{ (github.event_name == 'pull_request') }}
+          is_pr: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
           docker_content_sha: ${{ needs.initialize.outputs.docker_content_sha }}
           github_token: ${{ secrets.GITHUB_TOKEN }}
     outputs:
@@ -386,7 +386,7 @@ jobs:
         uses: ./.github/actions/docker
         with:
           docker_service: webtest
-          is_pr: ${{ (github.event_name == 'pull_request') }}
+          is_pr: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
           docker_content_sha: ${{ needs.initialize.outputs.docker_content_sha }}
           github_token: ${{ secrets.GITHUB_TOKEN }}
     outputs:
@@ -463,7 +463,10 @@ jobs:
           # Set fetch-depth to 2 to make checkout faster for pull requests and cobalt_sandbox repo.
           # Set fetch-dept to 0 for non pull request workflows in production repo which is needed
           # to properly calculate build id.
-          fetch_depth: ${{ ( github.event_name == 'pull_request' || github.repository == 'youtube/cobalt_sandbox' ) && 2 || 0 }}
+          fetch_depth: >-
+            ${{ (github.event_name == 'pull_request' ||
+                 github.event_name == 'merge_group' ||
+                 github.repository == 'youtube/cobalt_sandbox') && 2 || 0 }}
           use_cache: true
 
       - name: Set Up Depot Tools
@@ -511,7 +514,8 @@ jobs:
     if: |
       needs.initialize.outputs.test_on_device == 'true' &&
         (
-          (github.event_name == 'pull_request' && github.event.pull_request.draft == false ) ||
+          (github.event_name == 'pull_request' && github.event.pull_request.draft == false) ||
+          github.event_name == 'merge_group' ||
           ((inputs.nightly == 'true' || github.event_name == 'schedule') && vars.RUN_ODT_TESTS_ON_NIGHTLY != 'False') ||
           (github.event_name == 'push' && vars.RUN_ODT_TESTS_ON_POSTSUBMIT != 'False')
         )
@@ -560,7 +564,8 @@ jobs:
     if: |
       needs.initialize.outputs.test_e2e == 'true' &&
         (
-          (github.event_name == 'pull_request' && github.event.pull_request.draft == false ) ||
+          (github.event_name == 'pull_request' && github.event.pull_request.draft == false) ||
+          github.event_name == 'merge_group' ||
           ((inputs.nightly == 'true' || github.event_name == 'schedule') && vars.RUN_ODT_TESTS_ON_NIGHTLY != 'False') ||
           (github.event_name == 'push' && vars.RUN_ODT_TESTS_ON_POSTSUBMIT != 'False')
         )
@@ -595,7 +600,8 @@ jobs:
     if: |
       needs.initialize.outputs.test_yts == 'true' &&
         (
-          (github.event_name == 'pull_request' && github.event.pull_request.draft == false ) ||
+          (github.event_name == 'pull_request' && github.event.pull_request.draft == false) ||
+          github.event_name == 'merge_group' ||
           ((inputs.nightly == 'true' || github.event_name == 'schedule') && vars.RUN_ODT_TESTS_ON_NIGHTLY != 'False') ||
           (github.event_name == 'push' && vars.RUN_ODT_TESTS_ON_POSTSUBMIT != 'False')
         )
@@ -658,6 +664,7 @@ jobs:
       needs.initialize.outputs.test_on_host == 'true' &&
       (
         github.event_name == 'pull_request' ||
+        github.event_name == 'merge_group' ||
         ((inputs.nightly == 'true' || github.event_name == 'schedule') && vars.RUN_ODT_TESTS_ON_NIGHTLY != 'False') ||
         (github.event_name == 'push' && vars.RUN_ODT_TESTS_ON_POSTSUBMIT != 'False')
       )
@@ -815,7 +822,10 @@ jobs:
         with:
           path: cobalt/src
           ref: ${{ github.sha }}
-          fetch_depth: ${{ ( github.event_name == 'pull_request' || github.repository == 'youtube/cobalt_sandbox' ) && 2 || 0 }}
+          fetch_depth: >-
+            ${{ (github.event_name == 'pull_request' ||
+                 github.event_name == 'merge_group' ||
+                 github.repository == 'youtube/cobalt_sandbox') && 2 || 0 }}
           use_cache: true
 
       - name: Set Up Depot Tools

.github/workflows/raspi-2-modular.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly:

.github/workflows/tvos.yaml

@@ -12,6 +12,9 @@ on:
       - main
       - experimental/*
       - feature/*
+  merge_group:
+    branches:
+      - main
   workflow_dispatch:
     inputs:
       nightly: