Thank you for the report.  Those crash dump ids correspond to partitionOutOfMemory exceptions.  @alph, could you please take a look?

Just now I tried to load up a 700MB heapsnapshot and hit this:

An error occurred when a call to method 'buildSnapshot' was requested
RangeError: Array buffer allocation failed
    at new ArrayBuffer (<anonymous>)
    at new Uint8Array (native)
    at HeapSnapshotWorker.JSHeapSnapshot._buildPostOrderIndex (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@ea2ea29d648ff1eddde17a09074e3ba943a21fd5/&can_dock=true&dockSide=undocked:969:702)
    at HeapSnapshotWorker.JSHeapSnapshot.initialize (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@ea2ea29d648ff1eddde17a09074e3ba943a21fd5/&can_dock=true&dockSide=undocked:897:2591)
    at new HeapSnapshotWorker.JSHeapSnapshot (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@ea2ea29d648ff1eddde17a09074e3ba943a21fd5/&can_dock=true&dockSide=undocked:1093:387)
    at HeapSnapshotWorker.HeapSnapshotLoader.buildSnapshot (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@ea2ea29d648ff1eddde17a09074e3ba943a21fd5/&can_dock=true&dockSide=undocked:1203:85)
    at HeapSnapshotWorker.HeapSnapshotWorkerDispatcher.dispatchMessage (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@ea2ea29d648ff1eddde17a09074e3ba943a21fd5/&can_dock=true&dockSide=undocked:1253:509)

But on a second attempt, it worked.

Is there some artificial limit being applied to the RAM usage of the profile viewer?

I have encountered this issue as well. I take a heap snapshot of a tab with high memory utilization (~900MB), and it fails during "Building postorder index"

Console:

An error occurred when a call to method 'buildSnapshot' was requested
TypeError: Cannot read property '546318' of undefined
    at HeapSnapshotWorker.JSHeapSnapshotNode.name (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https….appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:740:122)
    at HeapSnapshotWorker.JSHeapSnapshot._buildPostOrderIndex (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https….appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:505:119)
    at HeapSnapshotWorker.JSHeapSnapshot.initialize (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https…appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:425:2591)
    at new HeapSnapshotWorker.JSHeapSnapshot (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https….appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:680:240)
    at HeapSnapshotWorker.HeapSnapshotLoader.buildSnapshot (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https…d.appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:626:85)
    at HeapSnapshotWorker.HeapSnapshotWorkerDispatcher.dispatchMessage (chrome-devtools://devtools/bundled/heap_snapshot_worker.js?remoteBase=https….appspot.com/serve_file/@0e9a9a6f3676ae439b78cd9b3f62b4193c3ac7d5/:676:509)

kenton@corp.sandstorm.io: Could you please help if you have sample files which can be shared to reproduce the crash and Crash Ids by the latest relevant to this to investigate it further. 

Sorry, but as I mentioned before, all my examples are from our live production servers and thus may contain PII of our users, so I cannot share them.

The problem is that the the code path reached by the initialize method of
JSHeapSnapshot accesses a member _lazyStringCache before it is initialized.

Constructor of JSHeapSnapshot initializes its _lazyStringCache here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/devtools/front_end/heap_snapshot_worker/HeapSnapshot.js?dr=CSs&l=2418
But the call to initialize() is the line before it.

Please assign to pfeldman, as the errors are in code he added in December
in this commit:
https://chromium.googlesource.com/chromium/src/+/2d6dcff9ac896f34b48945276029371eacbecc6a%5E%21/third_party/WebKit/Source/devtools/front_end/heap_snapshot_worker/HeapSnapshot.js

The problem in comment 4 seems to be unrelated to the original one which is pure OOM. I'll take care of it.

It does _seem_ unrelated, but heap profiles on small sites work just fine.
This only crashes on my memory-hog app. Looking at it, it seems as though
it should always crash in that code path, but maybe that path isn't getting
hit on small snapshots?

I'm experiencing the issue from comment 4 too in Chrome 59.0.3071.36 with about the same stacktrace (slightly different line numbers).

A dependable way to trigger the issue is to pick Memory -> Take Heap Snapshot within Gmail with the Streak chrome extension installed (completing the sign-in to Streak within Gmail is not necessary first to reproduce the issue).

I agree with comment 7 that issue seems to be because in HeapSnapshotWorker.JSHeapSnapshot's constructor, `this._lazyStringCache = {}` needs to be moved up a line to run before `this.initialize()` instead of after. Making this change with a second devtools window while I'm taking a heap snapshot of gmail+streak causes the heap snapshot to work.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dd5a66b4a00a250bcf9476bd373544c4d75bd81c

commit dd5a66b4a00a250bcf9476bd373544c4d75bd81c
Author: alph <alph@chromium.org>
Date: Thu May 18 03:46:02 2017

DevTools: fix exception on heap snapshot error reporting.

The debug log may access node.name() property during initialize method.
Make sure the cache is allocated.

BUG= 691935 

Review-Url: https://codereview.chromium.org/2884403002
Cr-Commit-Position: refs/heads/master@{#472647}

[modify] https://crrev.com/dd5a66b4a00a250bcf9476bd373544c4d75bd81c/third_party/WebKit/Source/devtools/front_end/heap_snapshot_worker/HeapSnapshot.js