Support sourceing files in patches.

lib/compiler/implementation/scanner/scanner_task.dart

Index: lib/compiler/implementation/scanner/scanner_task.dart
diff --git a/lib/compiler/implementation/scanner/scanner_task.dart b/lib/compiler/implementation/scanner/scanner_task.dart
index 25793e774c993f9cb0d23a0c13d0d24d8eb33a77..182fead08241514bd337828cedf26eb0c202feab 100644
--- a/lib/compiler/implementation/scanner/scanner_task.dart
+++ b/lib/compiler/implementation/scanner/scanner_task.dart
@@ -58,10 +58,7 @@ class ScannerTask extends CompilerTask {
         }
       } else if (tag.isSource()) {
         tagState = checkTag(TagState.SOURCE, tag);
-        Script script = compiler.readScript(resolved, tag);
-        CompilationUnitElement unit =
-            new CompilationUnitElement(script, library);
-        compiler.withCurrentElement(unit, () => scan(unit));
+        compiler.scanner.sourceTagInLibrary(tag, resolved, library);
       } else if (tag.isResource()) {
         tagState = checkTag(TagState.RESOURCE, tag);
         compiler.reportWarning(tag, 'ignoring resource tag');
@@ -88,6 +85,16 @@ class ScannerTask extends CompilerTask {
   }
 
   /**
+   * Source a tag in the scope of [library]. The [path] given is used as is,

[Mads Ager (google), 2012/08/22 07:40:03]

Handle a source tag in the scope of [library]?

At least in my mind you source a file/script with a source tag, but you don't
source a tag?

[Anders Johnsen, 2012/08/22 13:02:27]

Done.

+   * any resolve should be done beforehand.

[Mads Ager (google), 2012/08/22 07:40:03]

any resolution

[Anders Johnsen, 2012/08/22 13:02:27]

Done.

+   */
+  void sourceTagInLibrary(ScriptTag tag, Uri path, LibraryElement library) {

[Mads Ager (google), 2012/08/22 07:40:03]

Rename. sourceScript? importSourceFromTag (to match importLibraryFromTag)?

[Anders Johnsen, 2012/08/22 13:02:27]

Done.

+    Script script = compiler.readScript(path, tag);
+    CompilationUnitElement unit = new CompilationUnitElement(script, library);
+    compiler.withCurrentElement(unit, () => compiler.scanner.scan(unit));
+  }
+
+  /**
    * Handle an import script tag by importing the referenced library into the
    * current library.
    * Returns the resolved library [Uri].