Fix the android symbolization 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 132 matching lines @@
 resize2fs android_emulator_sdk/sdk/system-images/android-23/x86/userdata.img 1G
 
 # Set filesystem parameter to continue on errors; Android doesn't like some
 # things e2fsprogs does.
 tune2fs -e continue android_emulator_sdk/sdk/system-images/android-23/x86/userdata.img
 ```
 
 ## Symbolizing Crashes
 
 Crash stacks are logged and can be viewed using adb logcat. To symbolize the
-traces, pipe the output through
-`third_party/android_platform/development/scripts/stack`. If you build in an
-output directory other than "out", pass
-`--chrome-symbols-dir=out_directory/{Debug,Release}/lib` to the script as well.
+traces, define `CHROMIUM_OUTPUT_DIR=$OUTDIR` where `$OUTDIR` is the argument you
+pass to `ninja -C`, and pipe the output through
+`third_party/android_platform/development/scripts/stack`. If
+`$CHROMIUM_OUTPUT_DIR` is unset, the script will search `out/Debug` and
+`out/Release`. For example:
+
+```shell
+# If you build with
+ninja -C out/Debug chrome_public_test_apk
+# You can run:
+adb logcat -d | third_party/android_platform/development/scripts/stack
+
+# If you build with
+ninja -C out/android chrome_public_test_apk
+# You can run:
+adb logcat -d | CHROMIUM_OUTPUT_DIR=out/android third_party/android_platform/development/scripts/stack
+# or
+export CHROMIUM_OUTPUT_DIR=out/android
+adb logcat -d | third_party/android_platform/development/scripts/stack
+```
 
 ## JUnit tests
 
 JUnit tests are Java unittests running on the host instead of the target device.
 They are faster to run and therefore are recommended over instrumentation tests
 when possible.
 
 The JUnits tests are usually following the pattern of *target*\_junit\_tests,
 for example, `content_junit_tests` and `chrome_junit_tests`.
 
@@ skipping 121 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.