Replace WIDEVINE_CDM_AVAILABLE with a gyp define 'enable_widevine_cdm'.

build/config/BUILD.gn

 # Copyright (c) 2013 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/allocator.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 
 declare_args() {
@@ skipping 33 matching lines @@
     defines += [ "ENABLE_NOTIFICATIONS" ]
   }
   if (enable_pepper_cdms) {
     # TODO(brettw) should probably be "=1"
     defines += [ "ENABLE_PEPPER_CDMS" ]
   }
   if (enable_browser_cdms) {
     # TODO(brettw) should probably be "=1"
     defines += [ "ENABLE_BROWSER_CDMS" ]
   }
+  if (enable_widevine) {
+    defines += [ "ENABLE_WIDEVINE=1" ]
+  }
+  if (widevine_cdm_is_component) {
+    defines += [ "WIDEVINE_CDM_IS_COMPONENT=1" ]
+  }
   if (enable_plugins) {
     defines += [ "ENABLE_PLUGINS=1" ]
   }
   if (enable_basic_printing || enable_print_preview) {
     # Convenience define for ENABLE_BASIC_PRINTING || ENABLE_PRINT_PREVIEW.
     defines += [ "ENABLE_PRINTING=1" ]
     if (enable_basic_printing) {
       # Enable basic printing support and UI.
       defines += [ "ENABLE_BASIC_PRINTING=1" ]
     }
@@ skipping 239 matching lines @@
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
       "Foundation.framework",
       "UIKit.framework",
     ]
   } else if (is_linux) {
     libs = [ "dl" ]
   }
 }