Copy shared libstdc++ as part of the build step for android. (#3394)

* Link statically stdlibc++ for android builds

* GN format

* Copy libstdcpp automatically

* add missing file

* whitespace fix

* GN format

* GN format

* Android ABI in ndk seems to be x86_64 rather than x86-64 in the cxx sources

* Update abi name to use underscore for x86_64 in the chiptool android readme as well

build/chip/java/BUILD.gn

@@ -0,0 +1,29 @@
+# Copyright (c) 2020 Project CHIP Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build_overrides/chip.gni")
+
+import("//build/config/android/config.gni")
+import("//build/config/android_abi.gni")
+
+# Place a copy of the shared c++ support library in the jni output directory
+# See:
+#   https://developer.android.com/ndk/guides/cpp-support
+#
+# Generally CHIP cannot ensure a single shared library per java application, so a shared
+# CPP support library is used
+copy("shared_cpplib") {
+  sources = [ "${android_ndk_root}/sources/cxx-stl/llvm-libc++/libs/${android_abi}/libc++_shared.so" ]
+  outputs = [ "${root_out_dir}/lib/jni/${android_abi}/libc++_shared.so" ]
+}

build/config/android_abi.gni

@@ -4,7 +4,7 @@ if (current_os == "android") {
   } else if (current_cpu == "arm64") {
     android_abi = "arm64-v8a"
   } else if (current_cpu == "x64") {
-    android_abi = "x86-64"
+    android_abi = "x86_64"
   } else if (current_cpu == "x86") {
     android_abi = "x86"
   } else {

src/android/CHIPTool/README.md

@@ -23,7 +23,7 @@ ABIs and corresponding values for `target_cpu`
 | armeabi-v7a | arm        |
 | arm64-v8a   | arm64      |
 | x86         | x86        |
-| x86-64      | x64        |
+| x86_64      | x64        |
 
 1. Checkout the CHIP repo
 
@@ -58,14 +58,4 @@ rsync -a out/android_arm64/lib/jni/* src/android/CHIPTool/app/src/main/jniLibs
     ## JAR and .so libraries will be copy to target directories.
     ```
 
-6. You will also need the "libc++\_shared.so" file in the jniLibs folder. This
-   file comes packaged with Android NDK and can be found under
-   `$ANDROID_NDK_HOME/sources/cxx-stl/llvm-libc++/libs/$TARGET`, e.g.
-
-    `rsync -a "${ANDROID_NDK_HOME}/sources/cxx-stl/llvm-libc++/libs/arm64-v8a/libc++_shared.so" src/android/CHIPTool/app/src/main/jniLibs/arm64-v8a/`
-
-    (Eventually hoping to not have to include this .so, but that needs some more
-    tweaking of the Android automake build rules. Include it in the interim to
-    be able to build the Android app).
-
-7. 'Gradle sync' the Android project and run.
+6. 'Gradle sync' the Android project and run.

src/controller/java/BUILD.gn

@@ -38,7 +38,10 @@ shared_library("jni") {
 android_library("java") {
   output_name = "CHIPController.jar"
 
-  data_deps = [ ":jni" ]
+  data_deps = [
+    ":jni",
+    "//build/chip/java:shared_cpplib",
+  ]
 
   sources = [
     "src/chip/devicecontroller/AndroidChipStack.java",

src/setup_payload/java/BUILD.gn

@@ -33,7 +33,10 @@ shared_library("jni") {
 android_library("java") {
   output_name = "SetupPayloadParser.jar"
 
-  data_deps = [ ":jni" ]
+  data_deps = [
+    ":jni",
+    "//build/chip/java:shared_cpplib",
+  ]
 
   sources = [
     "src/chip/setuppayload/OptionalQRCodeInfo.java",