Heapprofiler API

Not finished (needs HeapGraph, GarbageCollector)
Implemented:
HeapProfiler.getProfileHeaders
HeapProfiler.startTrackingHeapObjects
HeapProfiler.stopTrackingHeapObjects
HeapProfiler.getHeapSnapshot
HeapProfiler.removeProfile
HeapProfiler.clearProfiles
HeapProfiler.takeHeapSnapshot
HeapProfiler.addProfileHeader
HeapProfiler.addHeapSnapshotChunk
HeapProfiler.finishHeapSnapshot
HeapProfiler.reportHeapSnapshotProgress
HeapProfiler.lastSeenObjectId
HeapProfiler.heapStatsUpdate

Related: #185


The latest branch 2143 in Blink (http://src.chromium.org/blink/branches/chromium/) seems to still use `getProfileHeaders`. Where did you find the version that deprecates this command?