Remove dart:_vmservice and dart:vmservice_io from platform.dill.

tools/patch_sdk.dart

Index: tools/patch_sdk.dart
diff --git a/tools/patch_sdk.dart b/tools/patch_sdk.dart
index 64038458e20e667185fccd0c72cc514f3e8ffb32..90d996c098e2cfadfeb1ed1aacc20b8f9c8fad89 100644
--- a/tools/patch_sdk.dart
+++ b/tools/patch_sdk.dart
@@ -168,19 +168,6 @@ String _updateLibraryMetadata(String sdkOut, String libContents) {
       "profiler/profiler.dart",
       maturity: Maturity.DEPRECATED,
       documented: false),
-
-  "_vmservice": const LibraryInfo(
-      "vmservice/vmservice.dart",
-      implementation: true,
-      documented: false,
-      platforms: VM_PLATFORM),
-
-  "vmservice_io": const LibraryInfo(
-      "vmservice_io/vmservice_io.dart",
-      implementation: true,
-      documented: false,
-      platforms: VM_PLATFORM),
-
 ''');
   _writeSync(
       path.join(
@@ -214,6 +201,7 @@ _copyExtraVmLibraries(String sdkOut, Map<String, String> locations) {
     _writeSync(libraryOut, readInputFile(libraryIn));
   }
   locations["vmservice_io"] = "vmservice_io/vmservice_io.dart";
+  locations["_vmservice"] = "vmservice/vmservice.dart";

[siva, 2017/06/09 22:54:50]

Do we still need to copy the vmservice_io.dart, loader.dart and server.dart etc.
to the patched_sdk folder and add their locations to the map?

[sivachandra, 2017/06/12 20:39:43]

I think what you are saying is that, if the vmservice related scripts are not
going to be part of platform.dill anymore, then we do not need to copy them over
to the patched_sdk; One could potentially compile them directly from the source
tree. Is this correct?

My understanding is that, since we are compiling a "dart:*" library, the only
way currently is to trick the fasta compiler into thinking that
dart:vmservice_io is part of "platform". So, to do this trick, we copy the
vmservice_io related files over to patched_sdk. That way, the compiler can
resolve dart:vmservice_io when it sees it in patched_sdk.

[Siggi Cherem (dart-lang), 2017/06/14 00:12:39]

It is actually possible to avoid the copying if we set here the location of
vmservice.dart in the source tree instead. This wasn't possible a couple weeks
ago, but now the input to the compiler is a .json file describining where to
find the sources. That .json file is created using this `locations` map here.
Note that to make it work this needs to be a relative path from the the json
file, which is emitted in the patched_sdk folder (e.g.
out/ReleaseX64/patched_sdk/libraries.json) and there may be small differences
depending on the architecture (win/mac/linux).

Just to be clear. We still need to copy the SDK libraries that contain
patch-files until we add patching support in fasta.

Question: do you need to continue using `dart:*` URIs for these libraries? Or
can they be a regular script or a script with a native extension? If you must
use dart:*, then we can skip the copying, if however it is possible to make them
a script, I'd rather move in that direction.

 }
 
 _applyPatch(SdkLibrary library, String sdkLibIn, String patchIn, String sdkOut,