fuchsia: Magenta -> Zircon

Includes a Fuchsia SDK update, and a lot of mx_ -> zx_, et al.

Sets CHROMIUM_ROLLING_MAGENTA_TO_ZIRCON=1 as a global define
temporarily to support for 3-sided rolls of third_party DEPS.

Requires https://chromium-review.googlesource.com/c/v8/v8/+/668751 to
have landed and rolled.

Requires boringssl roll with similar change to have landed
https://chromium-review.googlesource.com/c/chromium/src/+/668704.

[email protected],[email protected],[email protected],[email protected]
[email protected]

Bug: 765754, 707030
Change-Id: I6c2ad37b3c5b13c2a3a98da6e1ff9160ad2de949
Reviewed-on: https://chromium-review.googlesource.com/669139
Commit-Queue: Scott Graham <[email protected]>
Reviewed-by: David Benjamin <[email protected]>
Reviewed-by: Tom Sepez <[email protected]>
Reviewed-by: Ken Rockot <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#502678}

• DEPS[diff]
• base/BUILD.gn[diff]
• base/debug/stack_trace_fuchsia.cc[diff]
• base/fuchsia/default_job.cc[diff]
• base/fuchsia/default_job.h[diff]
• base/fuchsia/scoped_mx_handle.h[Deleted - diff]
• base/fuchsia/scoped_zx_handle.h[Added - diff]
• base/memory/shared_memory_fuchsia.cc[diff]
• base/memory/shared_memory_handle.h[diff]
• base/memory/shared_memory_handle_fuchsia.cc[diff]
• base/memory/shared_memory_unittest.cc[diff]
• base/message_loop/message_loop.cc[diff]
• base/message_loop/message_loop.h[diff]
• base/message_loop/message_pump_fuchsia.cc[diff]
• base/message_loop/message_pump_fuchsia.h[diff]
• base/metrics/field_trial.cc[diff]
• base/process/kill_fuchsia.cc[diff]
• base/process/launch.h[diff]
• base/process/launch_fuchsia.cc[diff]
• base/process/process.h[diff]
• base/process/process_fuchsia.cc[diff]
• base/process/process_handle.h[diff]
• base/process/process_handle_fuchsia.cc[diff]
• base/process/process_util_unittest.cc[diff]
• base/rand_util_fuchsia.cc[diff]
• base/sys_info_fuchsia.cc[diff]
• base/test/launcher/test_launcher.cc[diff]
• base/threading/platform_thread.h[diff]
• base/threading/platform_thread_posix.cc[diff]
• base/time/time.h[diff]
• base/time/time_fuchsia.cc[diff]
• base/trace_event/heap_profiler_allocation_register_posix.cc[diff]
• build/config/fuchsia/BUILD.gn[diff]
• build/fuchsia/runner_common.py[diff]
• content/browser/browser_main_loop.cc[diff]
• content/browser/tracing/tracing_controller_impl.cc[diff]
• ipc/handle_attachment_fuchsia.cc[diff]
• ipc/handle_attachment_fuchsia.h[diff]
• ipc/handle_fuchsia.cc[diff]
• ipc/handle_fuchsia.h[diff]
• ipc/ipc_message_attachment.cc[diff]
• mojo/edk/embedder/platform_channel_pair_fuchsia.cc[diff]
• mojo/edk/embedder/platform_handle.cc[diff]
• mojo/edk/embedder/platform_handle.h[diff]
• mojo/edk/embedder/platform_handle_utils_fuchsia.cc[diff]
• mojo/edk/system/channel.cc[diff]
• mojo/edk/system/channel.h[diff]
• mojo/edk/system/channel_fuchsia.cc[diff]
• mojo/edk/system/platform_wrapper_unittest.cc[diff]
• mojo/public/c/system/platform_handle.h[diff]
• mojo/public/cpp/system/platform_handle.cc[diff]
• net/base/net_errors_posix.cc[diff]