Add CHANGELOG entries for Dartium and dart:html changes

CHANGELOG.md

Index: CHANGELOG.md
diff --git a/CHANGELOG.md b/CHANGELOG.md
index af686c5ac3c1dff7b29a7c0b91903e259e3f4898..9d40bb940ef114ce8fa24da07ec6e8f4cc18abdc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,7 +32,16 @@
 * `dart:developer`
   * Added `Timeline` class for interacting with Observatory's timeline feature.
   * Added `ServiceExtensionHandler`, `ServiceExtensionResponse`, and `registerExtension` which enable developers to provide their own VM service protocol extensions.
-  
+
+* `dart:html`
+  * The return type of some APIs changed from `double` to `num`. Dartium is now
+    using
+    JS interop for most operations. JS does not distinguish between numeric

[kevmoo, 2015/11/11 22:00:49]

Folks should only see issues when running in checked-mode, right? Might want to
mention that...

[Alan Knight, 2015/11/11 23:00:12]

Hmm. I was thinking it was more than that, but I'm not seeing any operations on
double that aren't on int. The reverse case has several, but it looks like,
other than checking runtimeType or similar, it might just be checked mode. Added
a sentence about it.

+    types, and will return a number as an int if it fits in an int. You may
+    need to insert a `toDouble()` call or accept `num`. Examples of APIs that
+    are affected include `Element.getBoundingClientRect` and
+    `TextMetrics.width`.
+
 * `dart:io`
   * **Breaking:** Secure networking has changed, replacing the NSS library
     with the BoringSSL library. `SecureSocket`, `SecureServerSocket`,
@@ -58,9 +67,24 @@
     * The corresponding `reference` properties on `ServerSocket` and
       `RawServerSocket` have been removed.
 
+* `dart:indexed_db`

[kevmoo, 2015/11/11 22:00:49]

Roll all of these under `dart:html` – a comma-separated list is fine

[Alan Knight, 2015/11/11 23:00:12]

Done.

+  * APIs returning double have changed to num. See `dart:html` discussion.
+
 * `dart:isolate`
   * `spawnUri` added an `environment` named argument.
 
+* `dart:svg`
+  * APIs returning double have changed to num. See `dart:html` discussion.
+
+* `dart:web_audio`
+  * APIs returning double have changed to num. See `dart:html` discussion.
+
+* `dart:web_gl`
+  * APIs returning double have changed to num. See `dart:html` discussion.
+
+* `dart:web_sql`
+  * APIs returning double have changed to num. See `dart:html` discussion.
+
 ### Tool changes
 
 * `docgen` and 'dartdocgen' no longer ship in the sdk. The `docgen` sources have
@@ -73,6 +97,16 @@
   of a number of issues uncovered by the first few non-observatory
   clients.  This is a potentially breaking change for clients.
 
+* Dartium has been substantially changed. Rather than using C++ calls into
+  Chromium internals for DOM operations it now uses JS interop.
+  The DOM objects in `dart:html` and related libraries now wrap
+  a JavaScript object and delegate operations to it. This should be
+  mostly transparent to users. However, performance and memory characteristics
+  may be different from previous versions. There may be some changes in which

[kevmoo, 2015/11/11 22:00:49]

What does it mean to be "wrapped as Dart objects"? How does it affect how I
code?

[Alan Knight, 2015/11/11 23:00:12]

Clarified.

+  DOM objects are wrapped as Dart objects, e.g. Window objects are always
+  returned as Dart, even when used cross-frame. We expect the change to using
+  JS interop will make it much simpler to update to new Chrome versions.
+
 ## 1.12.2 - 2015-10-21
 
 ### Core library changes