Add storage of class id and state bit to the profiler's Sample

Add storage of class id and state bit to the profiler's Sample

- Stop storing sp and fp in Sample. Both are not used after the stack walk
- Add AllocationSample bit to Sample's state_
- Add a metadata_ field to Sample
- Use metadata_ to store a class id when AllocationSample bit is set

R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/50842cd27ad31b6a378ffe40f3c8ba961bbbbec2

[Cutch, 2015-06-22 22:04:56]

johnmccutchan@google.com changed reviewers:
+ rmacnak@google.com

[rmacnak, 2015-06-22 22:23:19]

lgtm

https://codereview.chromium.org/1199473003/diff/1/runtime/vm/profiler.h
File runtime/vm/profiler.h (right):

https://codereview.chromium.org/1199473003/diff/1/runtime/vm/profiler.h#newco...
runtime/vm/profiler.h:162: lr_ = 0;
metadata = 0

[Cutch, 2015-06-23 13:47:13]

https://codereview.chromium.org/1199473003/diff/1/runtime/vm/profiler.h
File runtime/vm/profiler.h (right):

https://codereview.chromium.org/1199473003/diff/1/runtime/vm/profiler.h#newco...
runtime/vm/profiler.h:162: lr_ = 0;
On 2015/06/22 22:23:19, rmacnak wrote:
> metadata = 0

Done.

[Cutch, 2015-06-23 13:47:44]

Committed patchset #2 (id:20001) manually as
50842cd27ad31b6a378ffe40f3c8ba961bbbbec2 (presubmit successful).