Adding user doc section and core files for new site

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:
+
+  * Apache Ant
+  * The Android SDK: http://developer.android.com/sdk/
+
+    $ sudo apt-get install ant git

[jcgregorio, 2015/01/07 13:53:23]

~~~~
$ sudo apt-get install ant git
~~~~

+
+Check out the source code
+-------------------------
+
+Follow the instructions [here](../download) for downloading the Skia source. Modify .gclient to add the following line to
+the bottom, and then run gclient sync again:
+
+    target_os = ["android"]
+
+Inside your Skia checkout, `platform_tools/android` contains the Android setup
+scripts, Android specific dependencies, and the Android Sample App.
+
+Setup the Android SDK
+---------------------
+
+To finish setting up the Android SDK you need to download use the SDK to
+download the appropriate API level.  To do this simply go to the directory
+where you installed the SDK and run the following commands
+
+    # You may want to add this export to your shell's .bash_profile or .profile
+    export ANDROID_SDK_ROOT=/path/to/android/sdk
+
+    $ANDROID_SDK_ROOT/tools/android update sdk --no-ui --filter android-19

[jcgregorio, 2015/01/07 13:53:23]

space after $

+
+From here you will need to type 'y' to approve the license agreement and that
+is all.  You will then have downloaded the SDK for API level 19 (Android 4.4
+KitKat) which will be used to build the Skia SampleApp.  You can download as
+many other Android add-ons or APIs as you want, but you only are required to
+have this one in order to complete the Skia build process.
+
+Setup Environment for Android
+-----------------------------
+
+The Android build needs to set up some specific variables needed by both GYP
+and Make. We make this setup easy for developers by encapsulating all the
+details into a custom script that acts as a replacement for make.
+
+Custom Android Build Script
+---------------------------
+
+The android_ninja script is a wrapper for the ninja command (provided by
+depot_tools) and is specifically designed to work with the Skia's build
+system. To use the script you need to call it from Skia's trunk directory with
+the -d option plus any of the options or arguments you would normally pass to
+ninja (see descriptions of some of the other flags here).
+
+    export ANDROID_SDK_ROOT=/path/to/android/sdk
+    export PATH=$PATH:/path/to/depot_tools
+
+    cd skia
+    ./platform_tools/android/bin/android_ninja -d nexus_10 # or nexus_7, galaxy_nexus, etc...
+
+The -d option enables the build system to target the build to a specific
+architecture such as MIPS (generic), x86 (generic) and ARM (generic and device
+specific flavors for Nexus devices). This in turn allows Skia to take
+advantage of specific device optimizations (e.g. NEON instructions).
+
+Generate build file from GYP
+----------------------------
+
+We use the open-source gyp tool to generate build files from our multiplatform
+"gyp" files. While most other platforms enable you to regenerate these files
+using `./gyp_skia` it is recommend that you do NOT do this for Android.  Instead
+you can rely on it being run automatically by android_ninja.
+
+Faster rebuilds
+---------------
+
+You can use ccache to improve the speed of rebuilding:
+
+  # You may want to add this export to your shell's .bash_profile or .profile
+  export ANDROID_MAKE_CCACHE=[ccache]
+
+Build and run executables on the device
+---------------------------------------
+
+The build system packages the Skia executables as shared libraries.  As such,
+in order to run any executable on the device you must install the library and
+a launcher executable on your device.  To assist in this process there is a
+script called `android_run_skia` that is located in the
+`platform_tools/android/bin` directory.
+
+Run correctness tests
+---------------------
+
+First build the app and then run it on an attached device:
+
+    ./platform_tools/android/bin/android_ninja [-d device_id] dm
+    ./platform_tools/android/bin/android_run_skia dm # uploads and runs the dm binary on the attached device
+
+Run performance tests
+---------------------
+
+Since nanobench tests performance, it usually makes more sense to run it in
+Release mode.
+
+    BUILDTYPE=Release ./platform_tools/android/bin/android_ninja [-d device_id] nanobench
+
+    # uploads and runs the nanobench binary on the attached device
+    ./platform_tools/android/bin/android_run_skia --release nanobench
+
+If you pass nanobench SKP files, it will benchmark them too.
+
+    ./platform_tools/android/bin/[linux/mac]/adb push ../skp <dst> # <dst> is dir on device
+
+Finally to run the executable there are two approaches. The simplest of the
+two run the app on the device like you would do for gm or tests, however this
+approach will also produce the noisiest results.
+
+    # <input> is file/dir on device
+    ./platform_tools/android/bin/android_run_skia --release nanobench --skps <input>
+
+Build and run SampleApp
+-----------------------
+
+The SampleApp on Android provides a simple UI for viewing sample slides and gm images.
+
+    BUILDTYPE=Debug ./platform_tools/android/bin/android_ninja -d $TARGET_DEVICE
+
+Then, install the app onto the device:
+
+    ./platform_tools/android/bin/android_install_apk
+
+Finally to run the application you must navigate to the Skia Samples
+application using the application launcher on your device.
+
+Build tools
+-----------
+
+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.
+
+    # you can include additional arguments in quotes (e.g. "dm --nopdf")
+    ./platform_tools/android/bin/android_gdb_exe dm
+
+When the gdb client is ready, insert a breakpoint, and continue to let the
+program resume execution.
+