[Android] Refine loadUrl API

Add the url checking in loadUrl function.
[Android] Runtime Core API -- getUrl

Implement the getUrl API of XWalkView.
[Android] Use IPC to extend the API beyond Content

This provides cross-process implementation of miscellaneous
XWalkView functions that we need to poke WebKit directly to implement.
[Android] Runtime Core API -- clearCache

Implement the clearCache API.
Merge pull request #316 from gramakri-intel/master

mac: compile
runtime: Add allow-external-extensions-for-remote-sources switch

This enables remote applications to be able to load external extensions.

When 'allow-external-extensions-for-remote-sources' is passed, loading any external
extensions for the remote application will be allowed.
Merge pull request #317 from vcgomes/enable-remote-application

runtime: Add enable-remote-application switch
Roll chromium DEPS to include Tizen 2.1 touch fix.
Packaging: enable Tizen 2.1 multi-touch support build flag.
Merge pull request #318 from huningxin/roll_dep

Roll chromium DEPS to include Tizen 2.1 touch fix.
Merge pull request #319 from huningxin/packaging-mt

Packaging: enable Tizen 2.1 multi-touch support build flag.
Revert "packaging: Change the order we use to look for GL implementations."

This patch causes xwalk to crash on Tizen 2.1 device.

This reverts commit b4d228ccfad3a7e1901a9491b10cfd6f14b3200c.
Merge pull request #322 from huningxin/revert-gl-reorder

Revert "packaging: Change the order we use to look for GL implementation...
Make new canary version 1.28.2.
Tizen: Guess the GL implementation to use by poking the file system.

We need to use EGL on Tizen Mobile devices and OSMesa in the emulator (the
EGL implementation in 2.1 does not work as expected in the emulator and
crashes Crosswalk).

The solution is two-fold:
 1. Ship libosmesa.so separately in another package, called
    crosswalk-emulator-support.
 2. Based on the presence of certain shared libraries on the system,
    determine whether to use OSMesa (emulator), Desktop GL (PC and maybe
    IVI) or EGL (mobile).

Related to issue #272.
Define ENABLE_XI21_MT for the multi-touch support.

This patch introduced common.gypi to define variables that effect chromium
compile.
Merge pull request #343 from rakuco/guess-available-gl-implementation

Tizen: Guess the GL implementation to use by poking the file system.
[Android] Fix style issues
[Android] Add condition for android source files

Move android files from common sources, only include them in
condition of OS=="android".
Move xwalk_globals_android.* to android folder.
Merge pull request #341 from luxtella/xwalkdefine

Define ENABLE_XI21_MT for the multi-touch support.