Hey Alex: for posterity's sake, could you add some more details in this bug about why this is necessary?

(Also, please make sure to set the component for all bugs so they don't disappear into the ether. "OS" should probably be all)

This is necessary in order to enable all RAIL stages to be constructed while minimizing the size of the trace.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cd6ea329d3c2657c97e34ca24814779eb80b384a

commit cd6ea329d3c2657c97e34ca24814779eb80b384a
Author: alexandermont <alexandermont@chromium.org>
Date: Fri Aug 12 17:24:07 2016

Add RAIL tracing category to Chrome tracing.

Adds an additional rail tracing category, which includes each event that
is needed to generate rail stages in the trace. The purpose of this change is to allow metrics to access rail stage information while minimizing the size of the traces.

TBR=caseq@chromium.org, dalecurtis@chromium.org
BUG=636442

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2227293002
Cr-Commit-Position: refs/heads/master@{#411687}

[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/cc/debug/benchmark_instrumentation.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/app/content_main_runner.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/browser/browser_main_loop.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/browser/frame_host/navigator_impl.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/renderer/input/input_handler_manager.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/renderer/input/render_widget_input_handler.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/content/renderer/render_frame_impl.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/media/blink/video_frame_compositor.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/animation/Animation.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/dom/DocumentTiming.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/frame/FrameView.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/page/PageAnimator.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/paint/FramePainter.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/core/paint/PaintTiming.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/third_party/WebKit/Source/web/WebViewImpl.cpp
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/ui/events/blink/input_handler_proxy.cc
[modify] https://crrev.com/cd6ea329d3c2657c97e34ca24814779eb80b384a/ui/events/latency_info.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e82c2934a58c704b0d8f2663cbb85299ff8ddf6d

commit e82c2934a58c704b0d8f2663cbb85299ff8ddf6d
Author: catapult-deps-roller <catapult-deps-roller@chromium.org>
Date: Tue Aug 16 04:11:08 2016

Roll src/third_party/catapult/ c6e591c97..b6a06a871 (1 commit).

https://chromium.googlesource.com/external/github.com/catapult-project/catapult.git/+log/c6e591c97f6f..b6a06a87148e

$ git log c6e591c97..b6a06a871 --date=short --no-merges --format='%ad %ae %s'

BUG=636442

TBR=catapult-sheriff@chromium.org

Review-Url: https://codereview.chromium.org/2249003002
Cr-Commit-Position: refs/heads/master@{#412163}

[modify] https://crrev.com/e82c2934a58c704b0d8f2663cbb85299ff8ddf6d/DEPS