Once the |aPayload| argument to profile_add_marker() became a UniquePtr the
default value of nullptr caused compilation difficulties that could only be
fixed by #including ProfilerMarkerPayload.h into lots of additional places
(because the UniquePtr<T> instantiation required the T to be fully defined). To
get around this I just split profile_add_marker() into two functions, one with
1 argument and one with 2 arguments.
The patch also removes the definition of PROFILER_MARKER_PAYLOAD in the case
where MOZ_GECKO_PROFILER isn't defined. A comment explains why.
This patch is going to neutralize the threat of fingerprinting of performance API
by spoofing the value of performance timing into 0, making getEntries* functions
always returns an empty list and making mark() and measure() into NOP methods.
In addition, this patch changes nsContentUtils::ShouldResistFingerprinting() to
allow it can be called in both main thread and worker threads.
MozReview-Commit-ID: C8Jt7KEMe5e
This patch is adapted from Tor bug 1517.
To offer some protection against timing attacks by JS content pages, in this
patch we round the various time-exposing APIs (such as Date and
Event.timeStamps) to the nearest 100 ms when the pref "privacy.resistFingerprinting" is on.
MozReview-Commit-ID: eGucM9nGTn
Because ProfilerMarkerPayload is the main type defined in these files, and
because the next patch is going to introduce ProfilerMarker.{h,cpp}, which
would be confusingly similar to the old names.
