[Docs] Improve Android test instructions

docs/android_test_instructions.md

 # Android Test Instructions
 
 Device Setup Tests are runnable on physical devices or emulators. See the
 instructions below for setting up either a physical device or an emulator.
 
 [TOC]
 
 ## Physical Device Setup **ADB Debugging**
 
 In order to allow the ADB to connect to the device, you must enable USB
@@ skipping 76 matching lines @@
 
 Alternatively, you can create an run your own emulator using the tools provided
 by the Android SDK. When doing so, be sure to enable GPU emulation in hardware
 settings, since Chromium requires it to render.
 
 ## Building Tests
 
 It may not be immediately obvious where your test code gets compiled to, so here
 are some general rules:
 
+*  If your test code lives under /base, it will be built as part of the
+   base_unittests_apk.
 *  If your test code lives under /content, it will probably be built as part of
    the content_shell_test_apk
 *  If your test code lives under /chrome (or higher), it will probably be built
    as part of the chrome_public_test_apk
 *  (Please fill in more details here if you know them).
 
    NB: We used to call the chrome_public_test_apk the
    chromium_shell_test_apk. There may still be references to this kicking
    around, but wherever you see chromium_shell_test you should replace with
    chrome_public_test.
@@ skipping 177 matching lines @@
 See
 https://sites.google.com/a/chromium.org/dev/developers/testing/webkit-layout-tests
 
 ## Running GPU tests
 
 (e.g. the "Android Debug (Nexus 7)" bot on the chromium.gpu waterfall)
 
 See http://www.chromium.org/developers/testing/gpu-testing for details. Use
 --browser=android-content-shell. Examine the stdio from the test invocation on
 the bots to see arguments to pass to src/content/test/gpu/run\_gpu\_test.py.