mojom.gni: add a source set called ${target_name}_cpp_sources.

mojo/public/tools/bindings/mojom.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../../mojo_sdk.gni")
 
-# Generate C++ and JavaScript source files from mojom files. The output files
-# will go under the generated file directory tree with the same path as each
-# input file.
+# Generate C++/JavaScript/Java/Python/Dart/Go source files from mojom files. The
+# output files will go under the generated file directory tree with the same
+# path as each input file.
 #
 # If a mojom target is intended for use in a client repo where the location of
 # the Mojo SDK will be different than its location in the Mojo repo,
 # dependencies on the SDK should be specified relative to the parent directory
 # of the Mojo public SDK in |mojo_sdk_deps| rather than via absolute paths in
 # |deps|.
 #
 # Parameters:
 #
 #   sources (optional if one of the deps sets listed below is present)
@@ skipping 185 matching lines @@
   }
 
   source_set(target_name) {
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
     if (defined(invoker.testonly)) {
       testonly = invoker.testonly
     }
     if (defined(invoker.sources)) {
-      sources = process_file_template(invoker.sources, generator_cpp_outputs)
       data = process_file_template(invoker.sources, generator_js_outputs)
     }
 
     public_configs =
         rebase_path([ "mojo/public/build/config:mojo_sdk" ], ".", mojo_root)
 
     public_deps = rebase_path([ "mojo/public/cpp/bindings" ], ".", mojo_root)
+    if (defined(invoker.sources)) {
+      public_deps += [ ":${target_name}_cpp_sources" ]
+    }
     public_deps += rebased_mojo_sdk_public_deps
     if (defined(invoker.public_deps)) {
       public_deps += invoker.public_deps
     }
 
     deps = []
     if (defined(invoker.sources)) {
       deps += [ ":$generator_target_name" ]
     }
     deps += rebased_mojo_sdk_deps
@@ skipping 113 matching lines @@
     args = [
       "--base-dir=$rebase_import_from",
       "--zip-inputs=$rebase_zip_inputs",
       "--output=$rebase_output",
     ]
     if (defined(invoker.sources)) {
       args += [ "--link-inputs=$rebase_inputs" ]
     }
   }
 
+  if (defined(invoker.sources)) {
+    # The generated C++ source files. The main reason to introduce this target
+    # is so that mojo/public/cpp/bindings can depend on mojom interfaces without
+    # circular dependencies.
+    source_set("${target_name}_cpp_sources") {
+      if (defined(invoker.visibility)) {
+        visibility = target_visibility + invoker.visibility
+      }
+      if (defined(invoker.testonly)) {
+        testonly = invoker.testonly
+      }
+      sources = process_file_template(invoker.sources, generator_cpp_outputs)
+      public_configs =
+          rebase_path([ "mojo/public/build/config:mojo_sdk" ], ".", mojo_root)
+      deps = [ ":$generator_target_name" ]
+    }
+  }
+
   if (is_android) {
     import("//build/config/android/rules.gni")
 
     java_target_name = target_name + "_java"
     android_library(java_target_name) {
       deps = rebase_path([
                            "mojo/public/java:bindings",
                            "mojo/public/java:system",
                          ],
                          ".",
                          mojo_root)
 
       foreach(d, all_deps) {
         # Resolve the name, so that a target //mojo/something becomes
         # //mojo/something:something and we can append "_java" to get the java
         # dependency name.
         full_name = get_label_info(d, "label_no_toolchain")
         deps += [ "${full_name}_java" ]
       }
 
       if (defined(invoker.sources)) {
         srcjars = process_file_template(invoker.sources, generator_java_outputs)
       }
     }
   }
 }