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.

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

javatests/google/registry/proxy/quota/QuotaConfigTest.java

@@ -0,0 +1,92 @@
+// Copyright 2018 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.truth.Truth.assertThat;
+import static google.registry.testing.JUnitBackports.assertThrows;
+import static google.registry.util.ResourceUtils.readResourceUtf8;
+
+import google.registry.proxy.ProxyConfig.Quota;
+import org.joda.time.Duration;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.yaml.snakeyaml.Yaml;
+
+/** Unit Tests for {@link QuotaConfig} */
+@RunWith(JUnit4.class)
+public class QuotaConfigTest {
+
+  private QuotaConfig quotaConfig;
+
+  private static QuotaConfig loadQuotaConfig(String filename) {
+    return new QuotaConfig(
+        new Yaml()
+            .loadAs(readResourceUtf8(QuotaConfigTest.class, "testdata/" + filename), Quota.class),
+        "theProtocol");
+  }
+
+  private void validateQuota(String userId, int tokenAmount, int refillSeconds) {
+    assertThat(quotaConfig.hasUnlimitedTokens(userId)).isFalse();
+    assertThat(quotaConfig.getTokenAmount(userId)).isEqualTo(tokenAmount);
+    assertThat(quotaConfig.getRefillPeriod(userId))
+        .isEqualTo(Duration.standardSeconds(refillSeconds));
+    assertThat(quotaConfig.getProtocolName()).isEqualTo("theProtocol");
+  }
+
+  @Test
+  public void testSuccess_regularConfig() {
+    quotaConfig = loadQuotaConfig("quota_config_regular.yaml");
+    assertThat(quotaConfig.getRefreshPeriod()).isEqualTo(Duration.standardHours(1));
+    validateQuota("abc", 10, 60);
+    validateQuota("987lol", 500, 10);
+    validateQuota("no_match", 100, 60);
+  }
+
+  @Test
+  public void testSuccess_onlyDefault() {
+    quotaConfig = loadQuotaConfig("quota_config_default.yaml");
+    assertThat(quotaConfig.getRefreshPeriod()).isEqualTo(Duration.standardHours(1));
+    validateQuota("abc", 100, 60);
+    validateQuota("987lol", 100, 60);
+    validateQuota("no_match", 100, 60);
+  }
+
+  @Test
+  public void testSuccess_noRefresh_noRefill() {
+    quotaConfig = loadQuotaConfig("quota_config_no_refresh_no_refill.yaml");
+    assertThat(quotaConfig.getRefreshPeriod()).isEqualTo(Duration.ZERO);
+    assertThat(quotaConfig.getRefillPeriod("no_match")).isEqualTo(Duration.ZERO);
+  }
+
+  @Test
+  public void testFailure_getTokenAmount_throwsOnUnlimitedTokens() {
+    quotaConfig = loadQuotaConfig("quota_config_unlimited_tokens.yaml");
+    assertThat(quotaConfig.hasUnlimitedTokens("some_user")).isTrue();
+    IllegalStateException e =
+        assertThrows(IllegalStateException.class, () -> quotaConfig.getTokenAmount("some_user"));
+    assertThat(e)
+        .hasMessageThat()
+        .contains("User ID some_user is provisioned with unlimited tokens");
+  }
+
+  @Test
+  public void testFailure_duplicateUserId() {
+    IllegalArgumentException e =
+        assertThrows(
+            IllegalArgumentException.class, () -> loadQuotaConfig("quota_config_duplicate.yaml"));
+    assertThat(e).hasMessageThat().contains("Multiple entries with same key");
+  }
+}