Implement the DebugAnnotatorVk class, and plumb the EVENT macro in the
GL entrypoints to save a string of call info in the vector of all
GL calls in ContextVk.

Then add a vkCmdBeginDebugUtilsLabelEXT() call that includes the
OpenGL draw/dispatch call prior to any Vulkan Draw or Dispatch calls.
Also embedded under that label add a second
vkCmdBeginDebugUtilsLabelEXT() call labeled "OpenGL Commands" that
includes all of the OpenGL calls leading up to the draw/dispatch.
Each individual OpenGL call is then given its own
vkCmdBegin/EndDebugUtilsLabelEXT() pair so that the complete sequence
of GL calls leading up to a draw call is visible for each Draw.

Enable the OGL->VK mapping feature by setting
"angle_enable_trace = true" in GN args.

Note: This will create an ANGLE APK on Android that generally won't
work with games, unless launched by AGI (which provides the debug
utils extension).  A future version will disable these labels unless
the debug utils extension is found.

Bug: b/162068318
Bug: b/169243237
Change-Id: I09886f17fa9287528c12552698738ea1fe2a4b8c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2427557
Commit-Queue: Ian Elliott <ianelliott@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>