Generate web, devtools files into their own sub-dirs.

Source/web/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//third_party/WebKit/Source/bindings/bindings.gni")
 import("//third_party/WebKit/Source/build/make_file_arrays.gni")
 import("//third_party/WebKit/Source/config.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 import("//third_party/WebKit/Source/modules/modules.gni")
@@ skipping 97 matching lines @@
     sources += platform_web_unittest_files
   }
 }
 }
 
 make_file_arrays("picker_common") {
   resources = [
     "resources/pickerCommon.css",
     "resources/pickerCommon.js",
   ]
-  filename = "PickerCommon"
+  filename = "web/PickerCommon"
 }
 
 make_file_arrays("color_suggestion_picker") {
   resources = [
     "resources/colorSuggestionPicker.css",
     "resources/colorSuggestionPicker.js",
   ]
-  filename = "ColorSuggestionPicker"
+  filename = "web/ColorSuggestionPicker"
 }
 
 make_file_arrays("calendar_picker") {
   resources = [
     "resources/calendarPicker.css",
     "resources/calendarPicker.js",
     "resources/pickerButton.css",
     "resources/suggestionPicker.css",
     "resources/suggestionPicker.js",
   ]
-  filename = "CalendarPicker"
+  filename = "web/CalendarPicker"
 }