test improvement: dump window hierarchy line by line

Otherwise a large buffer gets truncated by logcat.

Change-Id: I491c622e1a7ccc2004b33ff6a473c196ca13b4f9
diff --git a/libraries/launcher-helper/src/android/support/test/launcherhelper/GoogleExperienceLauncherStrategy.java b/libraries/launcher-helper/src/android/support/test/launcherhelper/GoogleExperienceLauncherStrategy.java
index 5b5fe19..dec36fd 100644
--- a/libraries/launcher-helper/src/android/support/test/launcherhelper/GoogleExperienceLauncherStrategy.java
+++ b/libraries/launcher-helper/src/android/support/test/launcherhelper/GoogleExperienceLauncherStrategy.java
@@ -65,9 +65,12 @@
                 ByteArrayOutputStream baos = new ByteArrayOutputStream();
                 try {
                     mDevice.dumpWindowHierarchy(baos);
-                    Log.d(LOG_TAG, baos.toString());
                     baos.flush();
                     baos.close();
+                    String[] lines = baos.toString().split("\\r?\\n");
+                    for (String line : lines) {
+                        Log.d(LOG_TAG, line.trim());
+                    }
                 } catch (IOException ioe) {
                     Log.e(LOG_TAG, "error dumping XML to logcat", ioe);
                 }