[Android] Disable hw encoding/decoding acceleration for WebRTC

The flag hw encoding/decoding acceleration for WebRTC is enabled by
default, it is controlled through GPU black list, please see:
https://chromiumcodereview.appspot.com/10832356/
But crosswalk is ignoring GPU black list because of enabling WebGL.

Currently, it is also disabled on chrome for Android M31, more information
please see: http://code.google.com/p/chromium/issues/detail?id=305421

BUG=https://crosswalk-project.org/jira/browse/XWALK-41
[Android] Add the instrumentation test for external extension.

This patch is to create two unit tests for external extensions for runtime
client. Since there are two modes - shared and embedded modes which are
supported in runtime client, here two copies here.

To avoid duplicated data, a shared directory is created to store data and
some code which should be used by all other instrumentation tests. So
we don't need to copy them everywhere. All testing data should be put
in here in future.

Besides, an external Java extension implementation is needed and
it has to be in test shell apks together with some assets and can't be in
instrumentation test apks because test shells can't access assets in
other assets.

For future, we should avoid duplicated code for embedded shell and shared
shell. This is a TODO.

BUG=#986
[Android] Fixes #979 - Changes in test pages won't rebuild XWalkCoreTest

With testing, if the files in 'sources' get updated (touch or content
change), the 'none' type target won't get rebuilt.

Instead, 'variable': {'additional_input_paths'} works as wish, that how
this commit comes.

BUG=#979
[WiDi API] First commit for Presentation API implementation on Android

This commit is the first patch to implement Presentation API spec on
Android. It is intended to bring wireless display support into Web. The
new API is placed under 'navigator.presentation' namespace, and the
'displayavailable' property and its change event is implemented in this
commit by use of DisplayManager in Android SDK.

SPEC=http://otcshare.github.io/presentation-spec/index.html
BUG=https://github.com/crosswalk-project/crosswalk/issues/577
Merge pull request #971 from yinli/webrtc_yinli

[Android] Disable hw encoding/decoding acceleration for WebRTC
Merge pull request #983 from gaochun/cordova_xwalk

[Android] Add Java extension system files to xwalk core library project.
Merge pull request #991 from halton/android_test_gyp

[Android] Fixes #979 - Changes in test pages won't rebuild XWalkCoreTest
Merge pull request #965 from hmin/widi-android-part1

[WiDi API] First commit for Presentation API implementation on Android
Merge pull request #988 from yongsheng/extensionunit

[Android] Add the instrumentation test for external extension.
[Android] Implement loading app from manifest file.

When the Java method AppFromManifest() in Java class XWalkView is
called, the manifest string will be passed to c++ side, it will be
parsed by the manifest parser. If a valid target URL could be got,
it will be passed back to the Java side, the Java class XWalkContent
will navigate to target page with the URL.

To comunicate between C++ and Java, the following interfaces are
added to XWalkContent.java:
1. The native method nativeSetManifest().
2. The Java method onGetUrlFromManifest() called by native.
[Android] Add test case for loadAppFromManifest().

This patch contains the test case about loadAppFromManifest on
embedded and shared mode.
Invoke loadAppFromManifest on main thread, then get the title
and compare the two titles.

For embedded client test:
1. install XWalkRuntimeClientEmbeddedShell.apk
2. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientEmbeddedTest -v -f \
testLoadAppFromManifest

For shared client test:
1. install XWalkRuntimeLib.apk
2. install XWalkRuntimeClientShell.apk
3. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientTest -v -f testLoadAppFromManifest