Handle the "debug_devtools" build arg in GN builds

chrome/browser/devtools/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/features.gni")
+
 action("devtools_protocol_constants") {
   script = "//content/public/browser/devtools_protocol_constants_generator.py"
 
   blink_protocol = "//third_party/WebKit/Source/devtools/protocol.json"
   browser_protocol = "//content/browser/devtools/browser_protocol.json"
   inputs = [ blink_protocol, browser_protocol ]
   outputs = [
     "$target_gen_dir/devtools_protocol_constants.cc",
     "$target_gen_dir/devtools_protocol_constants.h",
   ]
 
   args = [ "chrome" ]
   args += rebase_path(outputs, root_build_dir)
   args += [ rebase_path(blink_protocol, root_build_dir) ]
   args += [ rebase_path(browser_protocol, root_build_dir) ]
 }
 
 # GYP version: chrome/chrome_debugger.gypi:debugger
 static_library("devtools") {
+  defines = []
+
   # Note: new sources and deps should be generally added in (!is_android) below.
   sources = [
     "devtools_network_conditions.cc",
     "devtools_network_conditions.h",
     "devtools_network_controller.cc",
     "devtools_network_controller.h",
     "devtools_network_interceptor.cc",
     "devtools_network_interceptor.h",
     "devtools_network_protocol_handler.cc",
     "devtools_network_protocol_handler.h",
     "devtools_network_transaction.cc",
     "devtools_network_transaction.h",
     "devtools_network_transaction_factory.cc",
     "devtools_network_transaction_factory.h",
     "devtools_protocol.cc",
     "devtools_protocol.h"
   ]
   sources += get_target_outputs(":devtools_protocol_constants")
 
-  # TODO(GYP)
-  #     ['debug_devtools==1', {
-  #       'defines': [
-  #         'DEBUG_DEVTOOLS=1',
-  #        ],
-  #     }],
+  if (debug_devtools) {
+    defines += [ "DEBUG_DEVTOOLS=1" ]

[brettw, 2014/09/25 20:40:53]

It would be nice to have a config somewhere that defines this so we don't need
to hardcode the name in several places. I notice there is an existing one in
chrome/browser/ui/BUILD.gn

It looks like WebKit also needs to be checked (not sure if you already did this
or knew about it). I see at least one "debug_devtools = false" in a file there
with a TODO.

Can we have a config in blink (since it defines what devtools are) that does
this, and then set that config on targets that need this value?

configs += [ "//third_party/WebKit/public:debug_devtools" ]
or something.

[apavlov, 2014/09/26 07:10:27]

Good point. I've got https://codereview.chromium.org/608523002/ where I fix the
Blink part. I've added you to the R list and created the "debug_devtools" config
as you suggest. Please take a look, as that should be landed first.

+  }
+
   if (is_win) {
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     cflags = [ "/wd4267" ]
   }
   configs += [ "//build/config/compiler:wexit_time_destructors" ]
 
   deps = [
     ":devtools_protocol_constants",
     "//base",
     "//content/public/browser",
@@ skipping 58 matching lines @@
       "devtools_toggle_action.h",
       "devtools_ui_bindings.cc",
       "devtools_ui_bindings.h",
       "devtools_window.cc",
       "devtools_window.h",
       "remote_debugging_server.cc",
       "remote_debugging_server.h"
     ]
   }
 }