Add in some infrastructure to make tracing of logical requests broken over async callbacks easier.

remoting/base/protocol/chromotocol.gyp

Index: remoting/base/protocol/chromotocol.gyp
diff --git a/remoting/base/protocol/chromotocol.gyp b/remoting/base/protocol/chromotocol.gyp
index bdcb845914e908a7e30ce026776c02fa097c82bc..f3167ad61723db35e501342a82742230a9953aca 100644
--- a/remoting/base/protocol/chromotocol.gyp
+++ b/remoting/base/protocol/chromotocol.gyp
@@ -69,6 +69,69 @@
         '<(out_dir)/chromotocol.pb.h',
       ],
     },
+
+    {
+      # Protobuf compiler / generate rule for trace.proto.
+      'target_name': 'trace_proto',
+      'type': 'none',
+      'sources': [
+        'trace.proto',
+      ],
+      'rules': [
+        {
+          'rule_name': 'genproto',
+          'extension': 'proto',
+          'inputs': [
+            '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)protoc<(EXECUTABLE_SUFFIX)',
+          ],
+          'outputs': [
+            '<(PRODUCT_DIR)/pyproto/<(RULE_INPUT_ROOT)_pb/'
+               '<(RULE_INPUT_ROOT)_pb2.py',
+            '<(out_dir)/<(RULE_INPUT_ROOT).pb.cc',
+            '<(out_dir)/<(RULE_INPUT_ROOT).pb.h',
+          ],
+          'action': [
+            '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)protoc<(EXECUTABLE_SUFFIX)',
+            '--proto_path=.',
+            './<(RULE_INPUT_ROOT)<(RULE_INPUT_EXT)',
+            '--cpp_out=<(out_dir)',
+            '--python_out=<(PRODUCT_DIR)/pyproto/<(RULE_INPUT_ROOT)_pb',
+          ],
+          'message': 'Generating C++ and Python code from <(RULE_INPUT_PATH)',
+        },
+      ],
+      'dependencies': [
+        '../../../third_party/protobuf2/protobuf.gyp:protoc#host',
+      ],
+      # This target exports a hard dependency because it generates header
+      # files.
+      'hard_dependency': 1,
+    },
+
+    {
+      'target_name': 'trace_proto_lib',
+      'type': '<(library)',
+      'export_dependent_settings': [
+        '../../../third_party/protobuf2/protobuf.gyp:protobuf_lite',
+        'trace_proto',
+      ],
+      'dependencies': [
+        '../../../third_party/protobuf2/protobuf.gyp:protobuf_lite',
+        'trace_proto',
+      ],
+      # This target exports a hard dependency because depedents require
+      # chromotocol_proto to compile.
+      'hard_dependency': 1,
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '<(SHARED_INTERMEDIATE_DIR)/protoc_out',
+        ],
+      },
+      'sources': [
+        '<(out_dir)/trace.pb.cc',
+        '<(out_dir)/trace.pb.h',
+      ],
+    },
   ],
 }