Modified README for docgen.

pkg/docgen/README.md

+docgen
+======
+
 A documentation generator for Dart.
+- - -
+The docgen tool takes in a file or directory as input and produces documentation
+for all `.dart` file it finds as YAML or JSON files. This outputs information 
+about all classes, variables, functions, and methods defined in the library and 
+its imported libraries.
 
-The docgen tool takes in a library as input and produces documentation
-for it as well as all libraries it imports and uses.
+### Generating Files & Uploading to Cloud Storage
 
-This outputs information about all classes, variables, functions, and
-methods defined in the library and its imported libraries.
+The viewer uses YAML files generated by the docgen package as the data 
+being displayed. These files are stored in Google Cloud Storage.
 
-## USAGE
+ - Run `python upload_docgen.py` to generate these files and upload them to 
+ Cloud Storage as a new version.
+- - -
+These tasks can be done separately if necessary:
 
-  dart docgen.dart path/to/file.dart
+##### 
+
+#### Generating YAML Files
+
+YAML files can be generated using the docgen package in the dart repository. 
+
+###### Usage 
+
+Run  `dart docgen.dart [OPTIONS] <path to directory or file>`
+
+###### Options available
+
+- `-h`, `--help` Prints help and usage information.
+- `-v`, `--verbose` Output more logging information.
+- `-j`, `--[no-]json` Outputs to JSON. Files are outputted to YAML by default.
+- `--include-private` Flag to include private declarations.
+- `--include-sdk` Flag to parse SDK Library files imported.
+- `--parse-sdk` Parses the SDK libraries only. (Ignores the path passed in.)
+- `--package-root` Sets the package root of the library being analyzed.
+
+###### Output Directory
+Documented libraries will be located at bin/docs in either YAML or JSON format 
+depending on options specified. There will also be a library_list.txt, 
+containing a list of all the libraries inside the docs folder. 
+
+To get more information on how to use the outputted documentation with 
+dartdoc-viewer, please take a look at the 
+[dartdoc-viewer documentation][dartdoc-viewer].
+
+[dartdoc-viewer]: https://github.com/dart-lang/dartdoc-viewer "Dartdoc-Viewer"
+
+#### Uploading to Cloud Storage
+
+To push new files to Google Cloud Storage for use by the viewer, use the 
+`gsutil` tool located at third_party/gsutil/gsutil in the Dart repository.
+
+ - Run `python gsutil -m cp -q -a public-read -r <folder> gs://dartlang-docgen`
+ to upload the specified folder to the viewer's bucket. Be sure to also upload 
+ a new VERSION file if the uploaded folder is to be used.**
+
+**Note that the bucket contains several numbered folders for each version of 
+the documentation. Run `python gsutil ls gs://dartlang-docgen` to see the file 
+layout. Follow this convention and update a new VERSION file when uploading 
+a new version of documentation. You can see the format of the VERSION file 
+by running `python gsutil cat gs://dartlang-docgen/VERSION`.