Rename snapshot, other user-visible parts of docgen to dartdocgen.

utils/apidoc/docgen.gyp

Index: utils/apidoc/docgen.gyp
diff --git a/utils/apidoc/docgen.gyp b/utils/apidoc/docgen.gyp
index 0cdd4ea4f7908e6141c6c9838b6227d2d6ba752e..f9fc55aaef20ad7f77f10551424ba5cdbe829f46 100644
--- a/utils/apidoc/docgen.gyp
+++ b/utils/apidoc/docgen.gyp
@@ -63,8 +63,12 @@
             '../../sdk/bin/dart.bat',
             '../../sdk/bin/dart2js',
             '../../sdk/bin/dart2js.bat',
+            # TODO(alanknight): The docgen name is deprecated in favour of
+            # dartdocgen, and should be removed eventually.
             '../../sdk/bin/docgen',
+            '../../sdk/bin/dartdocgen',
             '../../sdk/bin/docgen.bat',
+            '../../sdk/bin/dartdocgen.bat',
             '../../tools/only_in_release_mode.py',
             '<(PRODUCT_DIR)/dart-sdk/README',
             '<(SHARED_INTERMEDIATE_DIR)/pkg_files.stamp',
@@ -77,7 +81,7 @@
             '../../tools/only_in_release_mode.py',
             '<@(_outputs)',
             '--',
-            '<(PRODUCT_DIR)/dart-sdk/bin/docgen<(script_suffix)',
+            '<(PRODUCT_DIR)/dart-sdk/bin/dartdocgen<(script_suffix)',
             '--out=<(PRODUCT_DIR)/api_docs/docgen',
             '--include-sdk',
             '--no-include-dependent-packages',
@@ -90,7 +94,7 @@
             '--exclude-lib=try',
             '../../pkg'
           ],
-          'message': 'Running docgen: <(_action)',
+          'message': 'Running dartdocgen: <(_action)',
         },
       ],
     }