Roll polymer packages to version 0.3.4

pkg/observe/CHANGELOG.md

Index: pkg/observe/CHANGELOG.md
diff --git a/pkg/observe/CHANGELOG.md b/pkg/observe/CHANGELOG.md
index 53a425fa233aed01525d5276fb948b6f63008f3e..89cd3a36173496863416da708f6f855bfc4fd3e4 100644
--- a/pkg/observe/CHANGELOG.md
+++ b/pkg/observe/CHANGELOG.md
@@ -3,6 +3,17 @@
 This file contains highlights of what changes on each version of the observe
 package.
 
+#### Pub version 0.12.0-dev
+  * Updated to match [observe-js#e212e74][e212e74] (release 0.3.4)
+  * ListPathObserver has been deprecated  (it was deleted a while ago in
+    observe-js). We plan to delete it in a future release. You may copy the code
+    if you still need it.
+  * PropertyPath now uses an expression syntax including indexers. For example,
+    you can write `a.b["m"]` instead of `a.b.m`.
+  * **breaking change**: PropertyPath no longer allows numbers as fields, you
+    need to use indexers instead. For example, you now need to write `a[3].d`
+    instead of `a.3.d`.
+
 #### Pub version 0.11.0-dev
   * PathObserver.value= no longer discards changes (this is in combination with
     a change in template_binding and polymer to improve interop with JS custom
@@ -20,3 +31,7 @@ package.
     import 'package:observe/mirrors_used.dart', and that will add a @MirrorsUsed
     annotation that preserves properties and classes labeled with @reflectable
     and properties labeled with @observable.
+  * Updated to match [observe-js#0152d54][0152d54]
+
+[0152d54]: https://github.com/Polymer/observe-js/blob/0152d542350239563d0f2cad39d22d3254bd6c2a/src/observe.js
+[e212e74]: https://github.com/Polymer/observe-js/blob/e212e7473962067c099a3d1859595c2f8baa36d7/src/observe.js