update to polymer js 0.5.1

pkg/web_components/CHANGELOG.md

-#### Pub version 0.9.0+1
+#### 0.10.0
+  * Updated to the `0.5.1` js version.
+  * **Breaking Change** To remain consistent with the js repository all the
+    `platform.js` has been replaced with `webcomponents.js`. Also, the default
+    file is now unminified, and the minified version is called
+    `webcomponents.min.js`.
+
+#### 0.9.0+1
   * Remove all `.map` and `.concat.js` files during release mode.
 
-#### Pub version 0.9.0
+#### 0.9.0
   * Updated to platform version 0.4.2, internally a deprecated API was removed,
     hence the bump in the version number.
 
   * split dart_support.js in two. dart_support.js only contains what is
     necessary in order to use platform.js,
     interop_support.js/interop_support.html can be imported separately when
     providing Dart APIs for js custom elements.
 
-#### Pub version 0.8.0
+#### 0.8.0
   * Re-apply changes from 0.7.1+1 and also cherry pick 
     [efdbbc](https://github.com/polymer/CustomElements/commit/efdbbc) to fix
     the customElementsTakeRecords function.
   * **Breaking Change** The customElementsTakeRecords function now has an
     an optional argument `node`. There is no longer a single global observer,
     but one for each ShadowRoot and one for the main document. The observer that
     is actually used defaults to the main document, but if `node` is supplied
     then it will walk up the document tree and use the first observer that it
     finds.
 
-#### Pub version 0.7.1+2
+#### 0.7.1+2
   * Revert the change from 0.7.1+1 due to redness in FF/Safari/IE.
 
-#### Pub version 0.7.1+1
+#### 0.7.1+1
   * Cherry pick [f280d](https://github.com/Polymer/ShadowDOM/commit/f280d) and
     [165c3](https://github.com/Polymer/CustomElements/commit/165c3) to fix
     memory leaks.
 
-#### Pub version 0.7.1
+#### 0.7.1
   * Update to platform version 0.4.1-d214582.
 
-#### Pub version 0.7.0+1
+#### 0.7.0+1
   * Cherry pick https://github.com/Polymer/ShadowDOM/pull/506 to fix IOS 8.
 
-#### Pub version 0.7.0
+#### 0.7.0
   * Updated to 0.4.0-5a7353d release, with same cherry pick as 0.6.0+1.
   * Many features were moved into the polymer package, this package is now
     purely focused on polyfills.
   * Change Platform.deliverDeclarations to 
     Platform.consumeDeclarations(callback).
   * Cherry pick https://github.com/Polymer/ShadowDOM/pull/505 to fix mem leak.
 
-#### Pub version 0.6.0+1
+#### 0.6.0+1
   * Cherry pick https://github.com/Polymer/ShadowDOM/pull/500 to fix
     http://dartbug.com/20141. Fixes getDefaultComputedStyle in firefox.
 
-#### Pub version 0.6.0
+#### 0.6.0
   * Upgrades to platform master as of 8/25/2014 (see lib/build.log for details).
     This is more recent than the 0.3.5 release as there were multiple breakages
     that required updating past that.
   * There is a bug in this version where selecting non-rendered elements doesn't
     work, but it shouldn't affect most people. See 
     https://github.com/Polymer/ShadowDOM/issues/495.
 
-#### Pub version 0.5.0+1
+#### 0.5.0+1
   * Backward compatible change to prepare for upcoming change of the user agent
     in Dartium.
 
-#### Pub version 0.5.0
+#### 0.5.0
   * Upgrades to platform version 0.3.4-02a0f66 (see lib/build.log for details).
 
-#### Pub version 0.4.0
+#### 0.4.0
   * Adds `registerDartType` and updates to platform 0.3.3-29065bc
     (re-applies the changes in 0.3.5).
 
-#### Pub version 0.3.5+1
+#### 0.3.5+1
   * Reverts back to what we had in 0.3.4. (The platform.js updates in 0.3.5 had
     breaking changes so we are republishing it in 0.4.0)
 
-#### Pub version 0.3.5
+#### 0.3.5
   * Added `registerDartType` to register a Dart API for a custom-element written
     in Javascript.
   * Updated to platform 0.3.3-29065bc
 
-#### Pub version 0.3.4
+#### 0.3.4
   * Updated to platform 0.2.4 (see lib/build.log for details)