Add android.jar for SDK version 15.

Bug:
Change-Id: Iab4c1da9e3dbb6cdc5a13daed3ff5752f08979bd

build.gradle

diff --git a/build.gradle b/build.gradle
index 234fe25..418474a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -268,6 +268,7 @@
         ],
         "third_party": [
                 "android_jar/lib-v14",
+                "android_jar/lib-v15",
                 "android_jar/lib-v19",
                 "android_jar/lib-v21",
                 "android_jar/lib-v24",

third_party/android_jar/lib-v15.tar.gz.sha1

diff --git a/third_party/android_jar/lib-v15.tar.gz.sha1 b/third_party/android_jar/lib-v15.tar.gz.sha1
new file mode 100644
index 0000000..e9ce20a
--- /dev/null
+++ b/third_party/android_jar/lib-v15.tar.gz.sha1
@@ -0,0 +1 @@
+fcbd85d969e36bdbda0a5a46aabc01331fec98b1
\ No newline at end of file