dart2js: add support for configuration-specific imports.

tests/compiler/dart2js/unparser_test.dart

Index: tests/compiler/dart2js/unparser_test.dart
diff --git a/tests/compiler/dart2js/unparser_test.dart b/tests/compiler/dart2js/unparser_test.dart
index 4b9a8153526ab75e44b94a19714829d0a817cd71..e19ed0ddae6e8361df1fcde5a14de4efa45e6f8f 100644
--- a/tests/compiler/dart2js/unparser_test.dart
+++ b/tests/compiler/dart2js/unparser_test.dart
@@ -98,6 +98,57 @@ testExport() {
   testUnparseTopLevelWithMetadata('export "søhest";');
 }
 
+testConditionalImport() {
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(some.dotted.id)"other";');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(id=="some str")"other";');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2";');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(some.dotted.id)"other" as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(id=="some str")"other" as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2"'
+      ' as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(some.dotted.id)"other" deferred as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest" if(id=="some str")"other" deferred as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2"'
+      ' deferred as fiskehest;');
+  testUnparseTopLevelWithMetadata(
+      'import "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2"'
+      ' deferred as fiskehest'
+      ' show foo,bar;');
+}
+
+testConditionalExport() {
+  testUnparseTopLevelWithMetadata(
+      'export "søhest" if(some.dotted.id)"other";');
+  testUnparseTopLevelWithMetadata(
+      'export "søhest" if(id=="some str")"other";');
+  testUnparseTopLevelWithMetadata(
+      'export "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2";');
+  testUnparseTopLevelWithMetadata(
+      'export "søhest"'
+      ' if(id=="some str")"other"'
+      ' if(id)"other2"'
+      ' show foo,bar;');
+}
+
 testPart() {
   testUnparseTopLevelWithMetadata('part "søhest";');
 }
@@ -383,6 +434,8 @@ main() {
   testLibraryName();
   testImport();
   testExport();
+  testConditionalImport();
+  testConditionalExport();
   testPart();
   testPartOf();
   testCombinators();