Remove the _cpp_sources target from mojom.

content/common/BUILD.gn

 # 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("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//ppapi/features/features.gni")
 import("//sandbox/features.gni")
@@ skipping 331 matching lines @@
   ]
 
   public_deps = [
     ":mojo_bindings",
     "//cc",
     "//gpu/command_buffer/common",
     "//ipc",
     "//third_party/WebKit/public:blink_headers",
   ]
   deps = [
-    # This looks needless as we have :mojo_bindings in public_deps, but it's
-    # needed because of allow_circular_includes_from.
-    ":mojo_bindings_cpp_sources",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//build/util:webkit_version",
     "//cc/ipc",
     "//cc/surfaces",
     "//components/discardable_memory/common",
     "//components/tracing",
     "//components/tracing:startup_tracing",
     "//content:resources",
     "//content/app/resources",
@@ skipping 12 matching lines @@
     "//ipc",
     "//ipc:mojom",
     "//media",
     "//media:shared_memory_support",
     "//media/base/ipc",
     "//media/capture",
     "//media/capture/ipc",
     "//media/gpu/ipc/client",
     "//media/gpu/ipc/common",
     "//media/midi",
-    "//media/midi:mojo_cpp_sources",
+    "//media/midi:mojo",
     "//mojo/common:common_base",
     "//mojo/edk/system",
     "//net",
     "//ppapi/features",
     "//sandbox",
     "//sandbox:sandbox_features",
     "//services/service_manager",
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/interfaces",
     "//services/service_manager/runner/common",
@@ skipping 22 matching lines @@
     "//ui/shell_dialogs",
     "//url",
     "//url/ipc:url_ipc",
   ]
 
   defines = []
   include_dirs = []
   libs = []
   ldflags = []
 
-  allow_circular_includes_from = [ ":mojo_bindings_cpp_sources" ]
+  allow_circular_includes_from = [ ":mojo_bindings" ]
 
   if (is_android && use_seccomp_bpf) {
     set_sources_assignment_filter([])
     sources += [
       "sandbox_linux/sandbox_bpf_base_policy_linux.cc",
       "sandbox_linux/sandbox_bpf_base_policy_linux.h",
     ]
     set_sources_assignment_filter(sources_assignment_filter)
   }
 
@@ skipping 165 matching lines @@
     "//ui/gfx/geometry/mojo",
     "//ui/gfx/mojo",
     "//url/mojo:url_mojom_gurl",
     "//url/mojo:url_mojom_origin",
   ]
 
   export_class_attribute = "CONTENT_EXPORT"
   export_define = "CONTENT_IMPLEMENTATION=1"
   export_header = "content/common/content_export.h"
 }