Update docs with instructions for debugging Android SampleApp.

site/user/quick/android.md

 Android
 =======
 
 Prerequisites
 -------------
 
 _Currently we only support building Skia for Android on a Linux or Mac host!_
 
 The following libraries/utilities are required in addition to those needed for a standard skia checkout:
 
@@ skipping 137 matching lines @@
 The Android platform does not support skdiff at this time.
 
 Clean up all generated files
 ----------------------------
 
     make clean
 
 Debugging on Android
 --------------------
 
-We support debugging on using a GDB wrapper script. The script loads the app
-onto the device, starts a gdbserver instance with that app, and then enters a
-GDB client shell on the host. Necessary symbol files are pulled from the
-device and placed into a temporary folder. The script does not build the app -
-you'll have to do that first.
+We support 2 modes of debugging on Android using GDB wrapper scripts. These
+scripts start a gdbserver instance on the device and then enter an interactive
+GDB client shell on your host. All necessary symbol files should
+be pulled from the device and placed into a temporary folder (android_gdb_tmp).
 
-    # you can include additional arguments in quotes (e.g. "dm --nopdf")
+Note: The debugging scripts do not build the app - you'll have to do that first.
+
+    # COMMAND LINE APPS
+    # include additional arguments in quotes (e.g. "dm --nopdf")
     ./platform_tools/android/bin/android_gdb_native dm
+    
+    # SAMPLE APP
+    # make sure you've installed the app on the device first
+    ./platform_tools/android/bin/android_gdb_app
 
 When the gdb client is ready, insert a breakpoint, and continue to let the
 program resume execution.