Consistently type check analysis server request parameters.

Consistently type check analysis server request parameters.

Introduces a class RequestDatum, which wraps request parameters (or
components thereof) and provides type checking and coercion.
RequestDatum also provides an operator[] so that nested parameters can
be type checked and coerced at every level of nesting.

Previously, our checking and coercion was ad-hoc, and as a result some
parameters weren't type checked at all.

R=brianwilkerson@google.com

Committed: https://code.google.com/p/dart/source/detail?r=35228

[Brian Wilkerson, 2014-04-21 22:12:32]

LGTM

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/protocol.dart (right):

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/protocol.dart:97: * Return the value of the
parameter with the given [name], or defaultValue
"defaultValue" --> "[defaultValue]"

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/protocol.dart:100: RequestDatum getParameter(String
name, dynamic defaultValue) {
Do we want a default default value, such as
  RequestDatum getParameter(String name, [dynamic defaultValue = null])

[Paul Berry, 2014-04-21 22:21:45]

Committed patchset #1 manually as r35228 (presubmit successful).

[Paul Berry, 2014-04-21 22:22:21]

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/protocol.dart (right):

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/protocol.dart:97: * Return the value of the
parameter with the given [name], or defaultValue
On 2014/04/21 22:12:32, Brian Wilkerson wrote:
> "defaultValue" --> "[defaultValue]"

Done.

https://codereview.chromium.org/245113006/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/protocol.dart:100: RequestDatum getParameter(String
name, dynamic defaultValue) {
On 2014/04/21 22:12:32, Brian Wilkerson wrote:
> Do we want a default default value, such as
>   RequestDatum getParameter(String name, [dynamic defaultValue = null])

I don't know.  Currently there's not really a need for it, since the only use of
this method is for server.createContext's packageMap parameter, and the default
that makes sense for that is {}.

I'll keep this in mind as I'm getting more commands implemented.