Add usage of test mode of java_aconfig_library.
Add local host unit test of contentlibs
Test: atest ContentLibs_test_host --host
Bug: 287644619
Change-Id: Ib99a3f2b692d3251d445a2e188325ee0b0b6b268
Add the Injection use case of Aconfig flag.
Add corresponding tests.
Test: atest AconfigDemo_ContentLibs_Test
Bug: 287644619
Change-Id: I47cea59764b2956644ad0c159945d3cdb3231c09
Add a simple app uses aconfig.
This app can demonstrate
1. declare aconfig flag
2. build aconfig flag in building system
3. generate aconfig java flag
4. use aconfig java flag in java code
Test: atest AconfigDemo_ContentProvide_Test
Bug: 280833426
Change-Id: Ieacbe4b2368a00872254dab1c87dc66c569fc30a
The Aconfig demo will be used as
1. As an example for aconfig code lab
2. As an example for user to learn Aconfig
Test: N/A
Bug: 287644619
Change-Id: Ida6c922fdd52caaecfadff99809a70fab8442814
