Include licenses in maven pom

Test: Manual checked pom that is generated by grade uploadArchives

Bug: 35018649
Change-Id: Ibc0fc09737fc327a8e5acc04cf88e3e27d633b01

src/main/groovy/android/support/SupportLibraryExtension.groovy

@@ -16,11 +16,38 @@
 
 package android.support;
 
+import org.gradle.api.Project
+
 /**
  * Extension for {@link SupportLibraryPlugin}.
  */
 class SupportLibraryExtension {
+    Project project
     String name;
     String description;
     String inceptionYear;
-}
+    Collection<License> licenses = [];
+
+    SupportLibraryExtension(Project project) {
+        this.project = project
+    }
+
+    License license(Closure closure) {
+        def license = project.configure(new License(), closure)
+        licenses.add(license)
+        return license
+    }
+
+    class License {
+        String name;
+        String url;
+
+        void url(String p) {
+            url = p
+        }
+
+        void name(String p) {
+            name = p
+        }
+    }
+}

src/main/groovy/android/support/SupportLibraryPlugin.groovy

@@ -42,7 +42,7 @@ class SupportLibraryPlugin implements Plugin<Project> {
     @Override
     public void apply(Project project) {
         SupportLibraryExtension supportLibraryExtension =
-                project.getExtensions().create("supportLibrary", SupportLibraryExtension);
+                project.getExtensions().create("supportLibrary", SupportLibraryExtension, project);
 
         project.apply(ImmutableMap.of("plugin", "com.android.library"));
         project.apply(ImmutableMap.of("plugin", ErrorProneBasePlugin.class));
@@ -142,6 +142,15 @@ class SupportLibraryPlugin implements Plugin<Project> {
                                 url 'http://www.apache.org/licenses/LICENSE-2.0.txt'
                                 distribution 'repo'
                             }
+
+                            supportLibraryExtension.getLicenses().each {
+                                SupportLibraryExtension.License supportLicense ->
+                                    license {
+                                        name supportLicense.name
+                                        url supportLicense.url
+                                        distribution 'repo'
+                                    }
+                            }
                         }
 
                         scm {