Update docs for profiling Content Shell on Android.

docs/profiling_content_shell_on_android.md

Index: docs/profiling_content_shell_on_android.md
diff --git a/docs/profiling_content_shell_on_android.md b/docs/profiling_content_shell_on_android.md
index 7fb21c288d25138e5d943a12ccc0c49730c122c7..3243ab3b5e3ce6166ec473389043318b33ed269b 100644
--- a/docs/profiling_content_shell_on_android.md
+++ b/docs/profiling_content_shell_on_android.md
@@ -73,14 +73,31 @@ requires going to “about phone” or “about tablet” and clicking the build
 7 times:
 http://androidmuscle.com/how-to-enable-usb-debugging-developer-options-on-nexus-4-and-android-4-2-devices/
 
+## Enable profiling
+
+Rebuild `content_shell_apk` with profiling enabled.
+
+With GYP (deprecated):
+
+    export GYP_DEFINES="$GYP_DEFINES profiling=1"
+    build/gyp_chromium
+    ninja -C out/Release content_shell_apk
+
+With GN:
+
+    gn args out/Profiling
+    # add "enable_profiling = true"
+    ninja -C out/Profiling content_shell_apk
+    export CHROMIUM_OUTPUT_DIR="$PWD/out/Profiling"
+
 ## Run a Telemetry perf profiler
 
 You can run any Telemetry benchmark with `--profiler=perf`, and it will:
 
 1.  Download `perf` and `perfhost`
-1.  Install on your device
-1.  Run the test
-1.  Setup symlinks to work with the `--symfs` parameter
+2.  Install on your device
+3.  Run the test
+4.  Setup symlinks to work with the `--symfs` parameter
 
 You can also run "manual" tests with Telemetry, more information here:
 http://www.chromium.org/developers/telemetry/profiling#TOC-Manual-Profiling---Android
@@ -88,6 +105,17 @@ http://www.chromium.org/developers/telemetry/profiling#TOC-Manual-Profiling---An
 The following steps describe building `perf`, which is no longer necessary if
 you use Telemetry.
 
+## Use `adb_profile_chrome`
+
+Even if you're not running a Telemetry test, you can use Catapult to
+automatically push binaries and pull the profile data for you.
+
+    build/android/adb_profile_chrome --browser=content_shell --perf
+
+While you still have to build, install and launch the APK yourself, Catapult
+will take care of creating the symfs etc. (i.e. you can skip the "not needed for
+Telemetry" steps below).
+
 ## Install `/system/bin/perf` on your device (not needed for Telemetry)
 
     # From inside the android source tree (not inside Chromium)
@@ -96,14 +124,6 @@ you use Telemetry.
     adb sync
     adb shell perf top # check that perf can get samples (don’t expect symbols)
 
-## Enable profiling
-
-Rebuild `content_shell_apk` with profiling enabled
-
-    export GYP_DEFINES="$GYP_DEFINES profiling=1"
-    build/gyp_chromium
-    ninja -C out/Release content_shell_apk
-
 ## Install ContentShell
 
 Install with the following:
@@ -167,7 +187,6 @@ Run the following:
     adb shell perf record -g -p 12345 sleep 5
     adb pull /data/perf.data
 
-
 ## Create the report
 
 1.  Run the following: