[DevTools] Scope common protocol infrastructure under Protocol namespace in a separate module.

third_party/WebKit/Source/devtools/BUILD.gn

Index: third_party/WebKit/Source/devtools/BUILD.gn
diff --git a/third_party/WebKit/Source/devtools/BUILD.gn b/third_party/WebKit/Source/devtools/BUILD.gn
index b4f532014f1ec62e2e6d6ffd8984f8cdda77bf97..65be523dd1b7c6dd3ee36978829cbeb4e6afa177 100644
--- a/third_party/WebKit/Source/devtools/BUILD.gn
+++ b/third_party/WebKit/Source/devtools/BUILD.gn
@@ -99,6 +99,10 @@ devtools_screencast_js_files = [
   "front_end/screencast/ScreencastApp.js",
   "front_end/screencast/ScreencastView.js",
 ]
+devtools_protocol_js_files = [
+  "front_end/protocol/Protocol.js",
+  "front_end/protocol/HostedMode.js",
+]
 devtools_sdk_js_files = [
   "front_end/sdk/ApplicationCacheModel.js",
   "front_end/sdk/Connections.js",
@@ -120,8 +124,6 @@ devtools_sdk_js_files = [
   "front_end/sdk/DOMModel.js",
   "front_end/sdk/HAREntry.js",
   "front_end/sdk/HeapProfilerModel.js",
-  "front_end/sdk/InspectorBackend.js",
-  "front_end/sdk/InspectorBackendHostedMode.js",
   "front_end/sdk/LayerTreeBase.js",
   "front_end/sdk/NetworkLog.js",
   "front_end/sdk/NetworkManager.js",
@@ -329,6 +331,7 @@ devtools_module_json_files = [
   "front_end/network/module.json",
   "front_end/platform/module.json",
   "front_end/profiler/module.json",
+  "front_end/protocol/module.json",
   "front_end/resources/module.json",
   "front_end/sass/module.json",
   "front_end/security/module.json",
@@ -871,9 +874,9 @@ devtools_core_files =
     devtools_common_js_files + devtools_components_js_files +
     devtools_emulation_js_files + devtools_host_js_files +
     devtools_main_js_files + devtools_platform_js_files +
-    devtools_sdk_js_files + devtools_toolbox_bootstrap_js_files +
-    devtools_ui_js_files + devtools_workspace_js_files +
-    devtools_persistence_js_files
+    devtools_protocol_js_files + devtools_sdk_js_files +
+    devtools_toolbox_bootstrap_js_files + devtools_ui_js_files +
+    devtools_workspace_js_files + devtools_persistence_js_files
 
 devtools_modules_js_files =
     devtools_accessibility_js_files + devtools_audits_js_files +