Added support for packaging specs of Android libraries.

Fixed googlesamples#174

Bug: 132070893
Change-Id: I28ca9f48ab08e9343d5e4e259f6354b64fee4c45

Author: Stewart Miles

source/PlayServicesResolver/scripts/download_artifacts.gradle

@@ -602,11 +602,7 @@ public class PackageSpecifier implements Comparable {
    * @returns Colon separated string.
    */
   public String getSpecString() {
-    List<String> components = componentStrings
-    if (artifactType && artifactType != "srcaar") {
-      components = components.dropRight(1) + [versionExpression]
-    }
-    return components.join(":")
+    return componentStrings.join(":")
   }
 
   /*
@@ -1455,7 +1451,7 @@ def testPackageSpecifierStrings() {
   [[PackageSpecifier.fromString("a-b:c-d:1.2.3@srcaar"),
     ["a-b:c-d:1.2.3@srcaar", "a-b:c-d", "a-b.c-d-1.2.3.aar"]],
    [PackageSpecifier.fromString("a-b:c-d:1.2.3@aar"),
-    ["a-b:c-d:1.2.3", "a-b:c-d", "a-b.c-d-1.2.3.aar"]],
+    ["a-b:c-d:1.2.3@aar", "a-b:c-d", "a-b.c-d-1.2.3.aar"]],
    [PackageSpecifier.fromString("a-b:c-d:1.2.3"),
     ["a-b:c-d:1.2.3", "a-b:c-d", "a-b.c-d-1.2.3"]],
    [PackageSpecifier.fromString("a-b:c-d"),

source/PlayServicesResolver/scripts/download_artifacts_test.gradle

@@ -274,6 +274,16 @@ createTestTask(
    "android.arch.core.common-1.0.0.jar\n" +
    "com.android.support.support-annotations-26.1.0.jar"])
 
+createTestTask(
+  "testDownloadAvailableWithCustomPackaging",
+  "Downloads a single artifact with custom packaging.",
+  "com.android.support:support-annotations:23.0.1@magic",
+  ["com.android.support.support-annotations-23.0.1.magic":
+   "com/android/support/support-annotations/23.0.1/" +
+   "support-annotations-23.0.1.magic"],
+  ["Copied artifacts:\n" +
+   "com.android.support.support-annotations-23.0.1.magic"])
+
 createTestTask(
   "testDownloadAvailableTwice",
   "Downloads a single artifact and it's dependencies from maven.",
@@ -342,7 +352,7 @@ createTestTask(
    "com.android.support.support-vector-drawable-24.0.0.aar",
    "Modified artifacts:\n" +
    "com.android.support:appcompat-v7:23.0.0 --> " +
-   "com.android.support:appcompat-v7:24.0.0"])
+   "com.android.support:appcompat-v7:24.0.0@aar"])
 
 createTestTask(
   "testDownloadSrcAar",
@@ -545,7 +555,7 @@ createTestTask(
    "org.test.psr.locked.new-common-1.5.0.aar\n" +
    "org.test.psr.locked.output-1.5.0.aar",
    "Modified artifacts:\n" +
-   "org.test.psr.locked:input:1.2.3 --> org.test.psr.locked:input:1.5.0"])
+   "org.test.psr.locked:input:1.2.3 --> org.test.psr.locked:input:1.5.0@aar"])
 
 createTestTask(
   "testVersionLockedAndNonVersionLocked",