Add ppapi, improve Windows GN build.

gpu/ipc/BUILD.gn

Index: gpu/ipc/BUILD.gn
diff --git a/components/tracing/BUILD.gn b/gpu/ipc/BUILD.gn
similarity index 50%
copy from components/tracing/BUILD.gn
copy to gpu/ipc/BUILD.gn
index c2e05190ad6e7a0996e2713071e35a4bea4525fe..8fdbe4298d87de4001c07ce0d3ea0e5ef3a0fd49 100644
--- a/components/tracing/BUILD.gn
+++ b/gpu/ipc/BUILD.gn
@@ -1,17 +1,17 @@
-# 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.
-
-source_set("tracing") {
-  sources = [
-    "child_trace_message_filter.cc",
-    "child_trace_message_filter.h",
-    "tracing_messages.cc",
-    "tracing_messages.h",
-  ]
-
-  deps = [
-    "//base",
-    "//ipc",
-  ]
-}
+# 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.
+
+source_set("ipc") {
+  sources = [
+    "ipc/gpu_command_buffer_traits.cc",

[scottmg, 2014/05/26 19:00:59]

extra ipc/ here

+    "ipc/gpu_command_buffer_traits.h",
+  ]
+
+  configs += [ "//third_party/khronos:khronos_headers" ]
+
+  deps = [
+    "//gpu/command_buffer/common",
+    "//ipc",
+  ]
+}