GN: Introduce templates.

webrtc/build/webrtc.gni

Index: webrtc/build/webrtc.gni
diff --git a/webrtc/build/webrtc.gni b/webrtc/build/webrtc.gni
index a6282b84feb11e38522988ea9e5c367e623b3493..a4e714dc0ac6ef210dfd24ff1c94adcf6d69e999 100644
--- a/webrtc/build/webrtc.gni
+++ b/webrtc/build/webrtc.gni
@@ -10,6 +10,7 @@ import("//build/config/arm.gni")
 import("//build/config/features.gni")
 import("//build/config/mips.gni")
 import("//build_overrides/webrtc.gni")
+import("//testing/test.gni")
 
 declare_args() {
   # Disable this to avoid building the Opus audio codec.
@@ -144,3 +145,97 @@ declare_args() {
 rtc_libvpx_dir = "//third_party/libvpx"
 rtc_libyuv_dir = "//third_party/libyuv"
 rtc_opus_dir = "//third_party/opus"
+
+###############################################################################
+# Templates
+#
+
+# Points to //webrtc/ in webrtc stand-alone or to //third_party/webrtc/ in
+# chromium.
+# We need absolute paths for all configs in templates as they are shared in
+# different subdirectories.
+webrtc_root = get_path_info("../", "abspath")
+
+# Common configs to remove or add in all rtc targets.
+rtc_remove_configs = []
+rtc_add_configs = []
+
+set_defaults("rtc_test") {
+  configs = []
+  configs_suppressions = []

[kjellander_webrtc, 2016/09/01 19:55:29]

I'm not fully happy with this name, as we're using "suppressions" for all the
memory tools etc to silence errors. What about just calling it 'remove_configs'
instead? Once we've started hunting down all the cases of
//build/config/clang:find_bad_constructs it's going to be rarely used anyway.

If you disagree I can probably be convinced to stick with 'configs_suppressions'
though...

+}
+
+set_defaults("rtc_source_set") {
+  configs = []
+  configs_suppressions = []
+}
+
+set_defaults("rtc_executable") {
+  configs = []
+  configs_suppressions = []
+}
+
+set_defaults("rtc_static_library") {
+  configs = []
+  configs_suppressions = []
+}
+
+template("rtc_test") {
+  test(target_name) {
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "configs",
+                             "configs_suppressions",
+                           ])
+    configs += invoker.configs
+    configs += rtc_add_configs
+    configs -= rtc_remove_configs
+    configs -= invoker.configs_suppressions
+  }
+}
+
+template("rtc_source_set") {
+  source_set(target_name) {
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "configs",
+                             "configs_suppressions",
+                           ])
+    configs += invoker.configs
+    configs += rtc_add_configs
+    configs -= rtc_remove_configs
+    configs -= invoker.configs_suppressions
+  }
+}
+
+template("rtc_executable") {
+  executable(target_name) {
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "configs",
+                             "configs_suppressions",
+                           ])
+    configs += invoker.configs
+    configs += rtc_add_configs
+    configs -= rtc_remove_configs
+    configs -= invoker.configs_suppressions
+  }
+}
+
+template("rtc_static_library") {
+  static_library(target_name) {
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "configs",
+                             "configs_suppressions",
+                           ])
+    configs += invoker.configs
+    configs += rtc_add_configs
+    configs -= rtc_remove_configs
+    configs -= invoker.configs_suppressions
+  }
+}