Migrate @Provides methods to @Binds methods where possible.

@Binds is a much more efficient way to delegate one binding to another in that:
  * The @Binds method does not need to be invoked
  * It does not generate an additional Provider implementation
  * An additional Provider does does not need to be instantiated
Future changes to Dagger's component processor will add even further benefits.

More information: []

ATTENTION REVIEWERS: This migration is being done with global approval.  Per-project approval is not required.

Tested:
    TAP train for global presubmit queue
    []
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=125980758

java/google/registry/dns/DnsModule.java

@@ -27,6 +27,7 @@ import static google.registry.request.RequestParameters.extractSetOfParameters;
 import com.google.appengine.api.taskqueue.Queue;
 import com.google.appengine.api.taskqueue.QueueFactory;
 
+import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 
@@ -42,13 +43,11 @@ import javax.servlet.http.HttpServletRequest;
 
 /** Dagger module for the dns package. */
 @Module
-public final class DnsModule {
+public abstract class DnsModule {
 
-  @Provides
+  @Binds
   @DnsWriterZone
-  static String provideZoneName(@Parameter(RequestParameters.PARAM_TLD) String tld) {
-    return tld;
-  }
+  abstract String provideZoneName(@Parameter(RequestParameters.PARAM_TLD) String tld);
 
   @Provides
   @Named(DNS_PULL_QUEUE_NAME)

java/google/registry/dns/writer/dnsupdate/DnsUpdateWriterModule.java

@@ -14,6 +14,7 @@
 
 package google.registry.dns.writer.dnsupdate;
 
+import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 
@@ -23,12 +24,10 @@ import javax.net.SocketFactory;
 
 /** Dagger module that provides a DnsUpdateWriter. */
 @Module
-public final class DnsUpdateWriterModule {
+public abstract class DnsUpdateWriterModule {
 
-  @Provides
-  static DnsWriter provideDnsWriter(DnsUpdateWriter dnsWriter) {
-    return dnsWriter;
-  }
+  @Binds
+  abstract DnsWriter provideDnsWriter(DnsUpdateWriter dnsWriter);
 
   @Provides
   static SocketFactory provideSocketFactory() {

java/google/registry/groups/GroupsModule.java

@@ -14,15 +14,13 @@
 
 package google.registry.groups;
 
+import dagger.Binds;
 import dagger.Module;
-import dagger.Provides;
 
 /** Dagger module for groups package. */
 @Module
-public final class GroupsModule {
+public abstract class GroupsModule {
 
-  @Provides
-  static GroupsConnection provideGroupsConnection(DirectoryGroupsConnection connection) {
-    return connection;
-  }
+  @Binds
+  abstract GroupsConnection provideGroupsConnection(DirectoryGroupsConnection connection);
 }

java/google/registry/request/Modules.java

@@ -32,6 +32,7 @@ import com.google.appengine.api.urlfetch.URLFetchServiceFactory;
 import com.google.appengine.api.users.UserService;
 import com.google.appengine.api.users.UserServiceFactory;
 
+import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 
@@ -138,11 +139,9 @@ public final class Modules {
    * <p>You must also use the {@link AppIdentityCredential} module.
    */
   @Module
-  public static final class UseAppIdentityCredentialForGoogleApisModule {
-    @Provides
-    static HttpRequestInitializer provideHttpRequestInitializer(AppIdentityCredential credential) {
-      return credential;
-    }
+  public abstract static class UseAppIdentityCredentialForGoogleApisModule {
+    @Binds
+    abstract HttpRequestInitializer provideHttpRequestInitializer(AppIdentityCredential credential);
   }
 
   /**

java/google/registry/tools/RegistryToolModule.java

@@ -14,6 +14,7 @@
 
 package google.registry.tools;
 
+import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 
@@ -24,17 +25,15 @@ import java.util.Random;
 
 /** Dagger module for Registry Tool. */
 @Module
-final class RegistryToolModule {
+abstract class RegistryToolModule {
 
   @Provides
   static RegistryToolEnvironment provideRegistryToolEnvironment() {
     return RegistryToolEnvironment.get();
   }
 
-  @Provides
-  static PasswordGenerator providePasswordGenerator(RandomPasswordGenerator passwordGenerator) {
-    return passwordGenerator;
-  }
+  @Binds
+  abstract PasswordGenerator providePasswordGenerator(RandomPasswordGenerator passwordGenerator);
 
   @Provides
   static Random provideRandom() {