Perfetto

Tracing service and probes:
* --continuous-dump in tools/java_heap_dump now keeps recording until it
receives CTRL+C.
* Add CLONE_SNAPSHOT triggers for non-destructive snapshots of the trace
buffer without tracing interruption.
UI:
* Add support for parsing large integers from Trace Processor into
bigint. This is the default behaviour for unknown fields and can
be enabled specifically via the LONG and LONG_NULL column types.
SDK:
* Changed the type of the static constexpr metadata on protozero
generated bindings from a function returning the metadata to
metadata itself. For a field 'foo' the variable kFoo previously
defined as:
`static constexpr FieldMetadata_Foo kFoo() = { return {}; };`
it is now defined as:
`static constexpr FieldMetadata_Foo kFoo;`
This is a breaking change for users who directly access field
metadata.
* The new DataSourceBase::OnFlush() method allows users to properly handle
Flush requests.

Identical to v33.0. Version was bumped to work around prebuilt infra failures.

All:
* Switched to a C++17-only project by removing C++11 opt-out. This completes
the migration started in v31.0.
SDK:
* Tracing::Initialize() can be called more than once to initialize different
backends separately.
* Reduce binary size impact of autogenerated code.

SDK:
* Fix MSVC warnings.

Trace Processor:
* Fix build on windows.

Tracing service and probes:
* Added an explicit TraceUuid packet. The tracing service now always
generates a UUID, even if TraceConfig.trace_uuid_msb/lsb is empty.
Trace Processor:
*
UI:
*
SDK:
* Add perfetto::Tracing::ActivateTriggers() function.
* Made it possible to declare track event categories in a C++ namespace
with PERFETTO_DEFINE_CATEGORIES_IN_NAMESPACE, allowing multiple category
sets to be used in one same translation unit. Correspondingly, the
PERFETTO_COMPONENT_EXPORT and PERFETTO_TRACK_EVENT_NAMESPACE macros have
been deprecated in favor of this new functionality.
* Deprecated the PERFETTO_COMPONENT_EXPORT macro in favor of
PERFETTO_DEFINE_CATEGORIES_IN_NAMESPACE_WITH_ATTRS.
* Added TracingInitArgs::enable_system_consumer configuration option, that
allows the linker to discard the consumer IPC, if not required.