Allow linking of library jars in building apk targets

build/java_apk.gypi

Index: build/java_apk.gypi
diff --git a/build/java_apk.gypi b/build/java_apk.gypi
index 507e0d5786bcd083dbd67cfbdb0abe8607bd0395..cbc79035c55ac7cb5acde65c19e14ecc1b5bfecb 100644
--- a/build/java_apk.gypi
+++ b/build/java_apk.gypi
@@ -39,6 +39,8 @@
 #    that are generated at build time. This should be set automatically by a
 #    target's dependencies. The .java files in these directories are not
 #    included in the 'inputs' list (unlike additional_src_dirs).
+#  library_jars_paths - The path to library jars to be included in the classpath.
+#    These will not be included into the final apk.
 #  input_jars_paths - The path to jars to be included in the classpath. This
 #    should be filled automatically by depending on the appropriate targets.
 #  is_test_apk - Set to 1 if building a test apk.  This prevents resources from
@@ -74,6 +76,7 @@
     'additional_input_paths': [],
     'create_density_splits%': 0,
     'language_splits': [],
+    'library_jars_paths': [],

[jbudorick, 2015/09/29 13:44:35]

can we initialize this to 

  [ <(android_sdk_jar) ]

and omit android_sdk_jar from the --classpath argument below?

[ctserng, 2015/09/29 13:54:33]

I'm not sure we can do this because the intention is for the top-level target to
define library_jars_paths, in which case this would force them to have to
remember to add 'android_sdk_jar' as well.

That being said, it's already included in the --bootclasspath so I'm wondering
if it might not even be necessary at all in --classpath?  (I'm not that familiar
with the difference in the 2 options).

[jbudorick, 2015/09/29 13:59:28]

AFAICT the two are different.

     'input_jars_paths': [],
     'library_dexed_jars_paths': [],
     'main_dex_list_path': '<(intermediate_dir)/main_dex_list.txt',
@@ -888,7 +891,7 @@
       'action': [
         'python', '<(DEPTH)/build/android/gyp/javac.py',
         '--bootclasspath=<(android_sdk_jar)',
-        '--classpath=>(input_jars_paths) <(android_sdk_jar)',
+        '--classpath=>(input_jars_paths) <(android_sdk_jar) >(library_jars_paths)',
         '--src-gendirs=>(gen_src_dirs)',
         '--javac-includes=<(javac_includes)',
         '--chromium-code=<(chromium_code)',