parse_xpk: Define HandleError() and its constants before using them.

The existing code to warn the user if the Python crypto modules were not
installed was simply not working, as HandleError() and
EXIT_CODE_CRYPTO_NOT_FOUND need to be defined before the former is called.
[Extensions] Add a test that another extension depends on another

In this test an extension ("another") depends on two other extensions ("outer"
and "outer.inner"), by using objects that are provided by those extensions.
[Mac] Don't use Aura for Mac

Aura is not ready for Mac currently. It has not been enabled for Mac in upstream.
Thus, it fails even during 'gclient sync' due to some duplicate keys in resource files.

More details:

https://crosswalk-project.org/jira/browse/XWALK-85
Merge pull request #1019 from yongsheng/revert577

Revert577
[Mac] Fix the build

[chromium-style] virtual methods with non-empty bodies shouldn't be declared inline.
[chromium-style] Complex constructor has an inlined body.
[chromium-style] Complex class/struct needs an explicit out-of-line destructor.
[chromium-style] virtual methods with non-empty bodies shouldn't be declared inline.

http://www.chromium.org/developers/coding-style/chromium-style-checker-errors
Merge pull request #1018 from poussa/mac-gclient-sync

[Mac] Don't use Aura for Mac
Merge pull request #994 from rakuco/py-use-before-definition

parse_xpk: Define HandleError() and its constants before using them.
[Android] Fix ExtensionBroadcast test

With load on demand enabled (the default now) instances are only created when
needed. This test is failing because it assumes that a new Extension instance
is created for the iframe, and as the code running in the iframe doesn't need
the any instances they are not created.

This fixes substitutes the assumption that the instance will be created, when
the context is created by explicitly calling the extension.

With this assumption fixed, the test can be enabled back.

BUG=#984
[Extensions] Pass to RP whether we use or not use extension process
Merge pull request #1024 from cmarcelo/let-rp-know-whether-ep-is-enabled

[Extensions] Pass to RP whether we use or not use extension process
[Extensions] Register external extensions when EP is disabled

Fix the bug of external extensions not working when
--disable-external-process flag was passed. This is the default behavior
for Android. The problem was that we were sending the extensions to RP
before adding the external ones.
Merge pull request #993 from vcgomes/nested-load-on-demand-test

[Extensions] Add a test that another extension depends on another
Merge pull request #1026 from cmarcelo/fix-disable-extension-process

[Extensions] Register external extensions when EP is disabled
Merge pull request #1013 from vcgomes/fix-android-test-with-load-on-demand

[Android] Fix ExtensionBroadcast test
Merge pull request #1022 from poussa/mac-compile-8

[Mac] Fix the build
[Android] Remove duplicated asset files for Android tests.

There are 3 instrumentation tests for different purposes. They use
some common files. However, currently these files are copied in
many places. This fix is to share all of these asset files in a
shared folder: test/android/data. If a test APK needs them, copy
them in the generated output folder.

This is the first step: share asset files. Next step is to share
Java code.

BUG=https://crosswalk-project.org/jira/browse/XWALK-95