Move global dependencies to BackendUsage

pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../universe/use.dart' show StaticUse;
 import '../universe/world_impact.dart'
@@ skipping 155 matching lines @@
           (isExtension &&
               (allClassesSelected || selectedClasses.contains(classElement)))) {
         newActiveClasses.add(classElement);
         Iterable<ConstructorElement> escapingConstructors =
             computeEscapingConstructors(classElement);
         for (ConstructorElement constructor in escapingConstructors) {
           impactBuilder
               .registerStaticUse(new StaticUse.foreignUse(constructor));
         }
         escapingConstructors
-            .forEach(compiler.globalDependencies.registerDependency);
+            .forEach(backend.backendUsage.registerGlobalDependency);
         // Force the generaton of the type constant that is the key to an entry
         // in the generated table.
         ConstantValue constant = makeTypeConstant(classElement);
         backend.computeImpactForCompileTimeConstant(
             constant, impactBuilder, false);
         backend.addCompileTimeConstantForEmission(constant);
       }
     }
     activeClasses.addAll(newActiveClasses);
     instantiatedClasses.removeAll(newActiveClasses);
@@ skipping 24 matching lines @@
           result.add(member);
         }
       }
     }
 
     classElement.forEachMember(selectGenerativeConstructors,
         includeBackendMembers: false, includeSuperAndInjectedMembers: false);
     return result;
   }
 }