Read package:browser .js files from barback rather than from packages directory.

Read package:browser .js files from barback rather than from packages directory.

The previous code assumes that the packages/ directory exists. This will no
longer be the case if the package-spec DEP is implemented. Also resolves a
breaking edge-case: if a pubspec.lock exists but the packages directory has
been deleted, pub build will terminate with a file not found.

BUG=
R=rnystrom@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44468

[Chris Bracken, 2015-03-12 21:52:16]

cbracken@google.com changed reviewers:
+ nweiz@google.com, rnystrom@google.com

[Bob Nystrom, 2015-03-12 22:36:08]

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
File sdk/lib/_internal/pub/lib/src/command/build.dart (left):

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:194: /// Returns the number of
files it copied.
Can you preserve this behavior? It should be fairly easy to do and the printed
output expects this.

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
File sdk/lib/_internal/pub/lib/src/command/build.dart (right):

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:97: .then((_) {
In pub, we tend to leave .then() hanging on the right, so like:

         return Future.wait(assets.map(_writeAsset)).then((_) {
           return _copyBrowserJsFiles(dart2JSEntrypoints, assets);
         }).then((_) {

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:194: Future
_copyBrowserJsFiles(Iterable<AssetId> entrypoints, AssetSet assets) {
Feel free to use async/await here to make your life easier. :)

[Chris Bracken, 2015-03-12 22:52:43]

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
File sdk/lib/_internal/pub/lib/src/command/build.dart (left):

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:194: /// Returns the number of
files it copied.
On 2015/03/12 22:36:08, Bob Nystrom wrote:
> Can you preserve this behavior? It should be fairly easy to do and the printed
> output expects this.

Is there a good reason to? The new code uses _writeOutputFile() which increments
the count (line 185).

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
File sdk/lib/_internal/pub/lib/src/command/build.dart (right):

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:97: .then((_) {
On 2015/03/12 22:36:08, Bob Nystrom wrote:
> In pub, we tend to leave .then() hanging on the right, so like:
> 
>          return Future.wait(assets.map(_writeAsset)).then((_) {
>            return _copyBrowserJsFiles(dart2JSEntrypoints, assets);
>          }).then((_) {

Done.

[Bob Nystrom, 2015-03-13 16:20:22]

lgtm

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
File sdk/lib/_internal/pub/lib/src/command/build.dart (left):

https://codereview.chromium.org/1000193004/diff/1/sdk/lib/_internal/pub/lib/s...
sdk/lib/_internal/pub/lib/src/command/build.dart:194: /// Returns the number of
files it copied.
On 2015/03/12 22:52:42, Chris Bracken wrote:
> On 2015/03/12 22:36:08, Bob Nystrom wrote:
> > Can you preserve this behavior? It should be fairly easy to do and the
printed
> > output expects this.
> 
> Is there a good reason to? The new code uses _writeOutputFile() which
increments
> the count (line 185).

Ack, my reading comprehension was bad here. Sorry.

[Chris Bracken, 2015-03-13 16:34:37]

Committed patchset #2 (id:20001) manually as 44468 (presubmit successful).