Change the inlining context from an enum to a class.

Change the inlining context from an enum to a class.

To support inlining in test contexts, the inlining context needs to have its
dispatched behavior and state.  This change introduces a context class
representing calls inlined for their value or solely for their effects.  The
intermediate array of exits is moved from the graph to the inlining context.
The implementation behavior is otherwise the same as before.

Committed: https://code.google.com/p/dart/source/detail?r=16965

[Florian Schneider, 2013-01-11 11:41:57]

LGTM.

[srdjan, 2013-01-11 21:40:25]

DBC

https://codereview.chromium.org/11856010/diff/1/runtime/vm/flow_graph_builder.h
File runtime/vm/flow_graph_builder.h (right):

https://codereview.chromium.org/11856010/diff/1/runtime/vm/flow_graph_builder...
runtime/vm/flow_graph_builder.h:44: intptr_t NumExits() { return
exits_.length(); }
const

https://codereview.chromium.org/11856010/diff/1/runtime/vm/flow_graph_builder...
runtime/vm/flow_graph_builder.h:65: InliningContext* inlining_context);
An alternative could be to pass an instance of class NotInliningContext : public
InliningContext.