Refactor function tick code and add test

Refactor function tick code and add test

- Make ProfileFunction ticking semantics consistent with ProfileCode.
- Refactor ProfileFunction trie building code.
- Add test for ProfileFunction trees.

R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/62ada2042cd36d2dcd42bd2f3db3393f6ed1d219

[Cutch, 2015-07-28 20:21:40]

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

[rmacnak, 2015-07-28 20:35:28]

lgtm

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service.cc
File runtime/vm/profiler_service.cc (right):

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:123: // Already ticket.
ticked

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:1241: for (intptr_t i = 0; i <
samples_->length(); i++) {
i -> sample_index

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:1252: for (intptr_t j = 0; j < sample->length();
j++) {
j -> frame_index

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_test.cc
File runtime/vm/profiler_test.cc (right):

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_test.cc...
runtime/vm/profiler_test.cc:464: // We should have one allocation sample.
one -> three

[Cutch, 2015-07-28 21:27:36]

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service.cc
File runtime/vm/profiler_service.cc (right):

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:123: // Already ticket.
On 2015/07/28 20:35:27, rmacnak wrote:
> ticked

Done.

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:1241: for (intptr_t i = 0; i <
samples_->length(); i++) {
On 2015/07/28 20:35:27, rmacnak wrote:
> i -> sample_index

Done here and elsewhere.

https://codereview.chromium.org/1261963002/diff/1/runtime/vm/profiler_service...
runtime/vm/profiler_service.cc:1252: for (intptr_t j = 0; j < sample->length();
j++) {
On 2015/07/28 20:35:27, rmacnak wrote:
> j -> frame_index

Done here and elsewhere.

[Cutch, 2015-07-28 21:28:49]

Committed patchset #2 (id:20001) manually as
62ada2042cd36d2dcd42bd2f3db3393f6ed1d219 (presubmit successful).