Move GCP proxy code to the old [] proxy's location

1. Moved code for the GCP proxy to where the [] proxy code used to live.
3. Corrected reference to the GCP proxy location.
4. Misc changes to make ErrorProne and various tools happy.

+diekmann to LGTM terraform whitelist change.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=213630560

java/google/registry/proxy/quota/QuotaConfig.java

@@ -0,0 +1,87 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.proxy.quota;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableMap;
+import google.registry.proxy.ProxyConfig.Quota;
+import google.registry.proxy.ProxyConfig.Quota.QuotaGroup;
+import org.joda.time.Duration;
+
+/** Value class that stores the quota configuration for a protocol. */
+public class QuotaConfig {
+
+  /** A special value of token amount that indicates unlimited tokens. */
+  public static final int SENTINEL_UNLIMITED_TOKENS = -1;
+
+  private final String protocolName;
+  private final int refreshSeconds;
+  private final QuotaGroup defaultQuota;
+  private final ImmutableMap<String, QuotaGroup> customQuotaMap;
+
+  /**
+   * Constructs a {@link QuotaConfig} from a {@link Quota}.
+   *
+   * <p>Each {@link QuotaGroup} is keyed to all the {@code userId}s it contains. This allows for
+   * fast lookup with a {@code userId}.
+   */
+  public QuotaConfig(Quota quota, String protocolName) {
+    this.protocolName = protocolName;
+    refreshSeconds = quota.refreshSeconds;
+    defaultQuota = quota.defaultQuota;
+    ImmutableMap.Builder<String, QuotaGroup> mapBuilder = new ImmutableMap.Builder<>();
+    quota.customQuota.forEach(
+        quotaGroup -> quotaGroup.userId.forEach(userId -> mapBuilder.put(userId, quotaGroup)));
+    customQuotaMap = mapBuilder.build();
+  }
+
+  @VisibleForTesting
+  QuotaGroup findQuotaGroup(String userId) {
+    return customQuotaMap.getOrDefault(userId, defaultQuota);
+  }
+
+  /**
+   * Returns if the given user ID is provisioned with unlimited tokens.
+   *
+   * <p>This is configured by setting {@code tokenAmount} to {@code -1} in the config file.
+   */
+  boolean hasUnlimitedTokens(String userId) {
+    return findQuotaGroup(userId).tokenAmount == SENTINEL_UNLIMITED_TOKENS;
+  }
+
+  /** Returns the token amount for the given {@code userId}. */
+  int getTokenAmount(String userId) {
+    checkState(
+        !hasUnlimitedTokens(userId), "User ID %s is provisioned with unlimited tokens", userId);
+    return findQuotaGroup(userId).tokenAmount;
+  }
+
+  /** Returns the refill period for the given {@code userId}. */
+  Duration getRefillPeriod(String userId) {
+    return Duration.standardSeconds(findQuotaGroup(userId).refillSeconds);
+  }
+
+  /** Returns the refresh period for this quota config. */
+  Duration getRefreshPeriod() {
+    return Duration.standardSeconds(refreshSeconds);
+  }
+
+  /** Returns the name of the protocol for which this quota config is made. */
+  String getProtocolName() {
+    return protocolName;
+  }
+}