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This reverts commit 65d50038.

Reason for revert: Causing LayoutTest failures e.g. https://uberchromegw.corp.google.com/i/chromium.mac/builders/Mac10.10%20Tests/builds/25167

Original change's description:
> Better interpolation of oscillator at low frequencies
> 
> For low frequencies, use a 3-point or 5-point Lagrange interpolation
> scheme to improve the accuracy of the oscillator instead of using
> simple linear interpolation.
> 
> For a typical context, the linear interpolator is used if the
> frequency >= 3.2 Hz; the 3-point, for 3.2 > frequency > 1.7 Hz; and
> the 5-point for all other cases.  Thus, typical use-cases are not
> impaired by this change.
> 
> Some benchmark results from running an oscillator for 1000 seconds in an
> offline context.  This is the time measured from startRendering()
> until the promise is delivered.  The SNR is the measured SNR between
> the test signal and a reference 440 Hz signal.  The linear time was
> the same before and after this CL.
> 
> linear:
> time: 1844.6 ms, stddev: 154.4
> SNR: 27.7 dB
> 
> 3-point:
> time: 2426.5 ms, stddev: 265.0
> SNR: 37.2 dB
> 
> 5-point:
> time: 2752.6 ms, stddev: 215.1
> SNR: 59.3 dB
> 
> 7-point (for reference, not used now):
> time: 3239.4 ms, stddev: 263.8
> SNR: 82.5 dB
> 
> Bug: 773507
> Test: Oscillator/osc-440hz.html
> Change-Id: Ib49fab4fb27738f4f02bd41f8adcc2e3b2dd2137
> Reviewed-on: https://chromium-review.googlesource.com/713576
> Commit-Queue: Raymond Toy <rtoy@chromium.org>
> Reviewed-by: Hongchan Choi <hongchan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#510133}

TBR=rtoy@chromium.org,hongchan@chromium.org

Change-Id: If59bb7f8169b077c35e5d735c6f6f19cc780d512
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 773507
Reviewed-on: https://chromium-review.googlesource.com/729719Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510257}