Blimp: create MessageDispatcher class.

blimp/common/compositor/BUILD.gn

Index: blimp/common/compositor/BUILD.gn
diff --git a/blimp/common/BUILD.gn b/blimp/common/compositor/BUILD.gn
similarity index 61%
copy from blimp/common/BUILD.gn
copy to blimp/common/compositor/BUILD.gn
index eaf5f1625cd6c5f1c72cad18894e5ec42fd02879..fb9ef98f79ce982d4be675c5dff52a3b29776e56 100644
--- a/blimp/common/BUILD.gn
+++ b/blimp/common/compositor/BUILD.gn
@@ -2,22 +2,18 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-component("blimp_common") {
+static_library("compositor") {
   sources = [
     # TODO(dtrainor): Remove this once the LayerTreeHost settings for Blimp
     # are finalized or are pushed from the server component.  See
     # crbug.com/527655.
-    "../../content/public/common/content_switches.cc",
-    "blimp_common_export.h",
-    "compositor/blimp_layer_tree_settings.cc",
-    "compositor/blimp_layer_tree_settings.h",
+    "../../../content/public/common/content_switches.cc",
+    "blimp_layer_tree_settings.cc",
+    "blimp_layer_tree_settings.h",
   ]
 
-  defines = [ "BLIMP_COMMON_IMPLEMENTATION=1" ]
-
   deps = [
     "//base",
-    "//blimp/common/proto",
     "//cc",
     "//skia",
     "//ui/gfx/geometry",