Explicitly set the pool for the stable and beta ci buckets.

If no explicit pool dimension is set, buildbucket implicitly requests
a pool with the bucket's long name.

Bug: 922150
Change-Id: I6edbce54bc2c32f2d4a9c44e16008dc8d8c47ecb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1877657Reviewed-by: Aaron Gable <agable@chromium.org>
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709100}

infra/config/generated/cr-buildbucket.cfg

@@ -9337,6 +9337,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9359,6 +9360,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9381,6 +9383,7 @@ buckets: <
       dimensions: "cores:2"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9402,6 +9405,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9440,6 +9444,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9462,6 +9467,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9484,6 +9490,7 @@ buckets: <
       dimensions: "cores:2"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"
@@ -9505,6 +9512,7 @@ buckets: <
       dimensions: "cores:8"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
+      dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:0"
       recipe: <
         name: "chromium"

infra/config/versioned/branches/beta/buckets/ci.star

 load('//versioned/vars/ci.star', 'vars')
 vars.bucket.set('ci-beta')
 
+load('//lib/builders.star', 'defaults')
+defaults.pool.set('luci.chromium.ci')
+
 load('//versioned/milestones.star', milestone='beta')
 exec('//versioned/milestones/%s/buckets/ci.star' % milestone)

infra/config/versioned/branches/stable/buckets/ci.star

 load('//versioned/vars/ci.star', 'vars')
 vars.bucket.set('ci-stable')
 
+load('//lib/builders.star', 'defaults')
+defaults.pool.set('luci.chromium.ci')
+
 load('//versioned/milestones.star', milestone='stable')
 exec('//versioned/milestones/%s/buckets/ci.star' % milestone)