Update ddms and profiling docs to include sample profiling.

Bug: 5866094

Change-Id: Ib97990ee2fc823416b3f41856b815d4092818f98
diff --git a/docs/html/tools/debugging/ddms.jd b/docs/html/tools/debugging/ddms.jd
index 1b59875..5822e27 100644
--- a/docs/html/tools/debugging/ddms.jd
+++ b/docs/html/tools/debugging/ddms.jd
@@ -204,6 +204,10 @@
 
     <li>Click the <strong>Start Method Profiling</strong> button.</li>
 
+    <li>In Android 4.4 and later, choose either trace-based profiling or sample-based profiling
+    with a specified sampling interval. For earlier versions of Android, only trace-based profiling
+    is available.</li>
+
     <li>Interact with your application to start the methods that you want to profile.</li>
 
     <li>Click the <strong>Stop Method Profiling</strong> button. DDMS stops profiling your