android_webview: support building a stub WebView.

android_webview/BUILD.gn

Index: android_webview/BUILD.gn
diff --git a/android_webview/BUILD.gn b/android_webview/BUILD.gn
index 5aa72f8301abd552bf2917939022fa1baf4fccde..b92298ba2dce4351024400bbba8af1969896be21 100644
--- a/android_webview/BUILD.gn
+++ b/android_webview/BUILD.gn
@@ -28,6 +28,11 @@ if (enable_resource_whitelist_generation) {
 system_webview_android_manifest =
     "$target_gen_dir/system_webview_apk/AndroidManifest.xml"
 
+# TODO(torne): uncomment this once Android is updated to support loading this

[jbudorick, 2017/02/28 16:36:27]

I think I'd prefer this be omitted until Android is updated w/ such support.
Until then, there's nothing to prevent this from bitrotting.

[michaelbai, 2017/02/28 18:58:39]

Agreed, since there is internal target, once Android is updated, you will
upstream internal target to here, and these commented code might already out of
date.

[Torne, 2017/03/01 10:56:29]

No, we won't upstream the internal target - it has a different name and
definition since it's the google-branded version. But, it's simple enough to
redefine it when it's useful, so I'll remove it.

[michaelbai, 2017/03/01 17:15:35]

Thanks, I actually thought about the same thing, 'to have public version of
internal target'

+# form of stub APK.
+#system_webview_stub_android_manifest =
+#    "$target_gen_dir/system_webview_stub_apk/AndroidManifest.xml"
+
 group("android_webview") {
   if (!use_webview_internal_framework) {
     deps = [
@@ -42,6 +47,20 @@ jinja_template("system_webview_manifest") {
   variables = [ "package=$system_webview_package_name" ]
 }
 
+# TODO(torne): uncomment this once Android is updated to support loading this
+# form of stub APK.
+#jinja_template("system_webview_stub_manifest") {
+#  input = "apk/java/AndroidManifest.xml"
+#  output = system_webview_stub_android_manifest
+#  variables = [
+#    "package=$system_webview_package_name",
+#    "library=libmonochrome.so",
+#    "donor_package=org.chromium.chrome",
+#    "minsdk=TBD",
+#    "targetsdk=TBD",
+#  ]
+#}
+
 webview_repack_locales("repack_locales") {
   input_locales = locales
   output_locales = locales
@@ -807,4 +826,15 @@ if (!use_webview_internal_framework) {
     ]
     apk_name = "SystemWebView"
   }
+  # TODO(torne): uncomment this once Android is updated to support loading this
+  # form of stub APK.
+  #android_apk("system_webview_stub_apk") {
+  #  android_manifest = system_webview_stub_android_manifest
+  #  android_manifest_dep = ":system_webview_stub_manifest"
+  #  deps = [
+  #    ":system_webview_resources",
+  #  ]
+  #  apk_name = "SystemWebViewStub"
+  #  generate_buildconfig_java = false
+  #}
 }