You are probably looking for a change made after 482902 (known good), but no later than 482905 (first known bad).
CHANGELOG URL:
  https://chromium.googlesource.com/chromium/src/+log/d95e4951a3bab57b4839e3a3d7e64d43c8079d42..19bd384f656790e8e409086b5b97a53b3a6f5921

Guessing https://chromium.googlesource.com/chromium/src/+/1894d423068be735560e0171922c833c4091b5d1.

Friendly ping to get an update on this issue marked as Blocker.

per-revision-bisect result also points to the same CL as pointed in C#1.

Last good build: 61.0.3143.0
First bad build: 61.0.3144.0

Changelog:
==========
https://chromium.googlesource.com/chromium/src/+log/8b4643f67dc1c6b142a152aa2b76c771287e3a22..1894d423068be735560e0171922c833c4091b5d1

Note: Worked fine on the latest canary(61.0.3150.0) of Windows and Linux. This is Mac specific.

A friendly reminder that M61 branch is coming soon on 07/20! Your bug is labelled as Stable ReleaseBlock, pls make sure to land the fix ASAP to trunk. This way we branch M61 from a high quality trunk. Thank you.

Friendly ping to get an update on this marked as Blocker.

Interesting, taking a look.

The color conversion being done here is landing in SkImage_Raster::onMakeColorSpace.

I instrumented the function to print the "before" and "after" getColor values.

The input color is
  fBitmap.getColor(30,38) = 80ffffff
  *fBitmap.getAddr(30,38) = 80808080

The output color is, depending on the monitor's color space
  dst.getColor(30,38) = 80adadad
  *dst.getAddr(30,38) = 80575757

The SkTransferFunctionBehavior is kIgnore. If I change the behavior to kRespect, then I get

The output color is, depending on the monitor's color space
  dst.getColor(30,38) = 80d9d9d9
  *dst.getAddr(30,38) = 806d6d6d

This is when using Apple's "Generic RGB" profile. If I switch to something closer to sRGB, then I sometimes end up with kRespect giving me 80ffffff/80808080 as the output color.

To read the documentation of SkTransferFunctionBehavior::kIgnore, this seems like the expected behavior, but I think that we'll want the kRespect behavior.

Actually, using kRespect is not an option:
https://cs.chromium.org/chromium/src/third_party/skia/src/image/SkImage_Gpu.cpp?rcl=312f4b24f96ff8c3f2bdb040b8167c09765992e4&l=954

I find it odd that this is the only instance of this bug that has come up so far -- shouldn't this affect any content?

Still looking more into why white isn't mapping to white...

Might also be related to  issue 747640 

URGENT - PTAL.
Your bug is labelled as Stable ReleaseBlock, pls make sure to land the fix and get it merged into the M61 branch #3163 ASAP to have enough baking time in Beta before Stable promotion. Thank you!

Know that this issue shouldn't block the release?  Remove the ReleaseBlock-Stable label.

Attaching output from P3 versus sRGB.

Talked offline w/Brian and Florin, and this is still somewhat mysterious.

Deleted: srgb.png 310 KB

	srgb.png 310 KB View Download

Deleted: p3.png 370 KB

	p3.png 370 KB View Download

Found the bug. It's in constructing the pixel conversion pipeline at:

https://cs.chromium.org/chromium/src/third_party/skia/src/core/SkConvertPixels.cpp?rcl=5f9b59b52db2b9a11d41bb7fa93ec5e5d6104236&l=304

We do ...

    SkAlphaType premulState = srcInfo.alphaType();
    if (kPremul_SkAlphaType == premulState && SkTransferFunctionBehavior::kIgnore == behavior) {
        pipeline.append(SkRasterPipeline::unpremul);
        premulState = kUnpremul_SkAlphaType;
    }

    SkColorSpaceTransferFn srcFn;
    if (isColorAware && srcInfo.gammaCloseToSRGB()) {
[*]     pipeline.append_from_srgb(srcInfo.alphaType());
    } else if (isColorAware && !srcInfo.colorSpace()->gammaIsLinear()) {
        SkAssertResult(srcInfo.colorSpace()->isNumericalTransferFn(&srcFn));
        pipeline.append(SkRasterPipeline::parametric_r, &srcFn);
        pipeline.append(SkRasterPipeline::parametric_g, &srcFn);
        pipeline.append(SkRasterPipeline::parametric_b, &srcFn);
    }

Notice that at the [*] we're using srcInfo.alphaType to do the srgb-to-linear conversion. But, in the previous step, we converted the alpha type from kPremul_SkAlphaType to kUnpremul_SkAlphaType.

Putting up a patch to fix this.

 Issue 749960  has been merged into this issue.

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/179849efe5f5bb20e7036bb6e5a9f4bb9ad8b2f1

commit 179849efe5f5bb20e7036bb6e5a9f4bb9ad8b2f1
Author: Christopher Cameron <ccameron@chromium.org>
Date: Mon Jul 31 20:39:37 2017

Fix premul state in from_srgb in convert_with_pipeline

Without this patch, the pipeline
1. converts to unpremultiplied
2. applies the sRGB transfer assuming the pixel is premultiplied

In step 2, we should assume the pixel is unpremultiplied.

Bug:738517
Change-Id: Ic11fcf64faa423577ccb1cfc0cfe96feb57db09a
Reviewed-on: https://skia-review.googlesource.com/28404
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

[modify] https://crrev.com/179849efe5f5bb20e7036bb6e5a9f4bb9ad8b2f1/src/core/SkConvertPixels.cpp

Requesting merge for M61

Your change meets the bar and is auto-approved for M61. Please go ahead and merge the CL to branch 3163 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), ketakid @(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://skia.googlesource.com/skia/+/218b516e7b2248bae53132b97822702dac4c8abc

commit 218b516e7b2248bae53132b97822702dac4c8abc
Author: Florin Malita <fmalita@chromium.org>
Date: Wed Aug 02 17:26:18 2017

Fix premul state in from_srgb in convert_with_pipeline

Without this patch, the pipeline
1. converts to unpremultiplied
2. applies the sRGB transfer assuming the pixel is premultiplied

In step 2, we should assume the pixel is unpremultiplied.

Bug:738517
Change-Id: Ic11fcf64faa423577ccb1cfc0cfe96feb57db09a
Reviewed-on: https://skia-review.googlesource.com/28404
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

No-Tree-Checks: true
No-Try: true
No-Presubmit: true
Cherry-Pick: 179849efe5f5bb20e7036bb6e5a9f4bb9ad8b2f1
Approval:  https://crbug.com/738517#c19 
Change-Id: I637716ca2b722b863491e2bd66f6c7ed7e1fac0e
Reviewed-on: https://skia-review.googlesource.com/30041
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

[modify] https://crrev.com/218b516e7b2248bae53132b97822702dac4c8abc/src/core/SkConvertPixels.cpp

Thanks fmalita for the merge!