Blimp: create MessageDispatcher class.

blimp/common/BUILD.gn

Index: blimp/common/BUILD.gn
diff --git a/blimp/common/BUILD.gn b/blimp/common/BUILD.gn
index eaf5f1625cd6c5f1c72cad18894e5ec42fd02879..1675ca4f8a476b505f80e5d7e8254918443e07ee 100644
--- a/blimp/common/BUILD.gn
+++ b/blimp/common/BUILD.gn
@@ -4,23 +4,20 @@
 
 component("blimp_common") {
   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",
+  ]
+
+  deps = [
+    "compositor",
+    "net",
   ]
 
   defines = [ "BLIMP_COMMON_IMPLEMENTATION=1" ]
+}
 
+group("unit_tests") {
+  testonly = true
   deps = [
-    "//base",
-    "//blimp/common/proto",
-    "//cc",
-    "//skia",
-    "//ui/gfx/geometry",
-    "//ui/gl",
+    "net:blimp_net_unit_tests",
   ]
 }