http: avoid having to call LowLevelHttpResponse.getContent() twice

https://codereview.appspot.com/13074043/

Author: Yaniv Inbar

google-http-client-android/src/main/java/com/google/api/client/extensions/android/json/AndroidJsonFactory.java

@@ -64,6 +64,7 @@ public static AndroidJsonFactory getDefaultInstance() {
   }
 
   /** Holder for the result of {@link #getDefaultInstance()}. */
+  @Beta
   static class InstanceHolder {
     static final AndroidJsonFactory INSTANCE = new AndroidJsonFactory();
   }

google-http-client/src/main/java/com/google/api/client/http/HttpRequest.java

@@ -24,6 +24,7 @@
 import com.google.api.client.util.StringUtils;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
@@ -968,8 +969,11 @@ public HttpResponse execute() throws IOException {
           response = new HttpResponse(this, lowLevelHttpResponse);
           responseConstructed = true;
         } finally {
-          if (!responseConstructed && lowLevelHttpResponse.getContent() != null) {
-            lowLevelHttpResponse.getContent().close();
+          if (!responseConstructed) {
+            InputStream lowLevelContent = lowLevelHttpResponse.getContent();
+            if (lowLevelContent != null) {
+              lowLevelContent.close();
+            }
           }
         }
       } catch (IOException e) {