[Tizen][Runtime Model] Using the xwalk logo image when icons are not given in manifest.json

The application button with default xwalk logo image will be placed on
home screen in Tizen if the icons field is not given in manifest.json.

BUG=https://crosswalk-project.org/jira/browse/XWALK-124
[Extension] Adding a Crash Extension and a crash "demo"
[Extension] Gracefully handle an ExtensionProcess crash.

This patch enables us to gracefully handle a crash from
ExtensionProcess. We use XWalkExtensionProcessHost::OnChannelError
since we can't really rely on XWalkExtensionProcessHost::OnProcessCrashed.
See a more complete explanation about this on the end of this commit message.

It is safe to rely on XWalkExtensionProcessHost::OnChannelError
since this function is called just before
BrowserChildProcessHostImpl::OnChildDisconnected gets called.
OnChildDisconnected() would, in turn, be the function that would
call our OnProcessCrashed(). For more information, please refer to
ChildProcessHostImpl::OnChannelError() from child_process_host_impl.cc.

This patch also adds the interface XWalkExtensionProcessHost::Delegate,
which now is implemented by XWalkExtensionService.
XWalkExtensionProcessHost::OnChannelError() calls then
Delegate::OnExtensionProcessDied().

For documentation reasons, I will elaborate on what happens when not
using zygote, which is the case of EP.
GetTerminationStatusImpl() from base/process/kill_posix.cc ends up
calling waitpid() with WNOHANG. If the extension process isn't ready
to reply its termination status by then, we won't block while waiting
for it and that function will return TERMINATION_STATUS_STILL_RUNNING
to BrowserChildProcessHostImpl::OnChildDisconnected(). When that happens,
OnProcessCrashed() ends up never being called. That is not the case
for OnChannelError(), thus we use that as our hook.
Using zygote would put the necessary infra-structure in place,
but it would also bring more than what we currently need.
Merge pull request #1123 from jeez/crash-handling

[Extensions] Handle ExtensionProcess crashes gracefully
[DBus] Add PropertyExporter and DBusManager classes

This commit bootstraps the xwalk/dbus directory with two classes we
intend to use when implementing the '--run-as-service' mode in Linux.

The 'DBusManager' is a convenience class that packages the creation of
the DBus thread and the bus connection. There need to be only one of
those for the whole Crosswalk, so it should be passed around for the
subsystems that need it.

The 'PropertyExporter' class is a partial implementation of a helper
class that exports the 'org.freedesktop.DBus.Properties' interface for a
certain 'dbus::ExportedObject'. It's interface is still incomplete, and
at the moment it will be focused on covering our use cases for
'--run-as-service'. Chromium have a infrastructure for dealing with
properties but only on the client-side, this class adds the server side.

Unit testing infrastructure, as well as basic sanity tests were
added. With these bootstrapped is easy to add new tests later. The new
target 'xwalk_all_tests' was added to include this module in the build
system.
Merge pull request #1142 from cmarcelo/xwalk-dbus

[DBus] Add PropertyExporter and DBusManager classes
Bump version to 3.32.40.0
Merge pull request #1140 from takethathe/icon

[Tizen][Runtime Model] Using the xwalk logo image when icons are not given in manifest.json
[Runtime Model] Add permissions handler for manifest.json

Permissions handler can parse the permissions field in manifest.json,
and save the permissions information into Application object as
ManifestData struct.
Merge pull request #1089 from takethathe/permissions_handler

[Runtime Model] Add permissions handler for manifest.json
[Runtime] RuntimeRegistry should belong to XWalkContentBrowserClient

RuntimeRegistry should stop being a singleton itself but rather should belong to XWalkContentBrowserClient which is supposed to be a "main" object holding the rest.