[Android] Implement the method of OnReceiveHttpAuthRequest() in runtime core
          and update the http authentication database interfaces.

1. Some web page has the requirement of http authentication, support
   this requirement by providing the method of OnReceiveHttpAuthRequest().
2. Update the http authentication database interfaces by removing the previous
   method of getInstance() and directly calling the constructor function
   of the class HttpAuthDatabase.

BUG=#788
[Android] Make prepare_r_java.py an executable

IDEs like eclipse are unable to run the program as an external builder
if they are not marked executable.

Also, use copy2 instead of copyfile to preserve 'x' bit in file mode.
[Android] Add eclipse build support for xwalk_core_library

Eclipse is a popular IDE for android development. So it's useful
to have this supported out of the box.

This change adds the .project, .classpath files required by Eclipse
for importing.
[Android] Refactor the python script to prepare xwalk core library

Use list of files/directories to avoid duplicated code for copying.
[Android] Add thread safety checking for XWalkView.

All XWalkView methods must be called on the UI thread.
Throw an exception when XWalkView methods are called from
other thread. So all unit test cases need to be refined for
this change.

BUG=https://crosswalk-project.org/jira/browse/XWALK-98
Merge pull request #1021 from ShDavidliu/runtime_core

[Android] Implement the method of OnReceiveHttpAuthRequest().
[Tizen][Runtime Model] Fix installer crash if icon is missing from manifest.

Installation crashes if the icon field is missing from manifest.json.
However, this behavior is not correct.

The installation should not crash even though no icon is provideded.

BUG=https://crosswalk-project.org/jira/browse/XWALK-110
Merge pull request #1033 from junmin-zhu/thread

[Android] Add thread safety checking for XWalkView.
Merge pull request #1055 from wang16/refactor_prepare_core_py

[Android] Refactor the python script to prepare xwalk core library
Merge pull request #992 from gramakri-intel/master

[Android] Eclipse build support for xwalk_core_library
Merge pull request #1062 from shaochangbin/issues

[Tizen][Runtime Model] Fix installer crash if icon is missing from manifest.
Bump version to 2.31.30.0
[Android] Add the test cases about onActivityResult.

This patch contains the test case about onActivityResult in shared
and embedded mode. It's for the runtime client.
Create a activity names "SecondActivity". In the runtime client activity,
it starts activity for result. In the second activity, it will create a new
intent, and transfer data to runtime client activity.

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

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 testOnActivityResult