Introduce components/display_compositor

We would like to share BufferQueue, GLHelper and later other parts
of content/browser/compositor in Mus. This CL introduces a new
display_compositor component and moves BufferQueue, GLHelper and
friends to components/display_compositor.

BUG=601867
TBR=ben@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1902463002

Cr-Commit-Position: refs/heads/master@{#388829}

• .gn[diff]
• BUILD.gn[diff]
• build/gn_migration.gypi[diff]
• cc/cc_tests.gyp[diff]
• components/components.gyp[diff]
• components/display_compositor.gypi[Added - diff]
• components/display_compositor/BUILD.gn[Added - diff]
• components/display_compositor/DEPS[Added - diff]
• components/display_compositor/OWNERS[Added - diff]
• components/display_compositor/buffer_queue.cc[Renamed from content/browser/compositor/buffer_queue.cc - diff]
• components/display_compositor/buffer_queue.h[Renamed from content/browser/compositor/buffer_queue.h - diff]
• components/display_compositor/buffer_queue_unittest.cc[Renamed from content/browser/compositor/buffer_queue_unittest.cc - diff]
• components/display_compositor/display_compositor_export.h[Added - diff]
• components/display_compositor/display_compositor_test_suite.cc[Added - diff]
• components/display_compositor/display_compositor_test_suite.h[Added - diff]
• components/display_compositor/gl_helper.cc[Renamed from content/browser/compositor/gl_helper.cc - diff]
• components/display_compositor/gl_helper.h[Renamed from content/browser/compositor/gl_helper.h - diff]
• components/display_compositor/gl_helper_benchmark.cc[Renamed from content/browser/compositor/gl_helper_benchmark.cc - diff]
• components/display_compositor/gl_helper_readback_support.cc[Renamed from content/browser/compositor/gl_helper_readback_support.cc - diff]
• components/display_compositor/gl_helper_readback_support.h[Renamed from content/browser/compositor/gl_helper_readback_support.h - diff]
• components/display_compositor/gl_helper_scaling.cc[Renamed from content/browser/compositor/gl_helper_scaling.cc - diff]
• components/display_compositor/gl_helper_scaling.h[Renamed from content/browser/compositor/gl_helper_scaling.h - diff]
• components/display_compositor/gl_helper_unittest.cc[Renamed from content/browser/compositor/gl_helper_unittest.cc - diff]
• components/display_compositor/run_all_unittests.cc[Added - diff]
• components/display_compositor/yuv_readback_unittest.cc[Renamed from content/browser/compositor/yuv_readback_unittest.cc - diff]
• content/browser/BUILD.gn[diff]
• content/browser/compositor/DEPS[diff]
• content/browser/compositor/gpu_process_transport_factory.cc[diff]
• content/browser/compositor/gpu_process_transport_factory.h[diff]
• content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc[diff]
• content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.h[diff]
• content/browser/compositor/image_transport_factory.h[diff]
• content/browser/compositor/image_transport_factory_browsertest.cc[diff]
• content/browser/compositor/owned_mailbox.cc[diff]
• content/browser/compositor/owned_mailbox.h[diff]
• content/browser/compositor/reflector_texture.cc[diff]
• content/browser/compositor/reflector_texture.h[diff]
• content/browser/compositor/surface_utils.cc[diff]
• content/browser/compositor/test/no_transport_image_transport_factory.cc[diff]
• content/browser/compositor/test/no_transport_image_transport_factory.h[diff]
• content/browser/media/capture/DEPS[diff]
• content/browser/media/capture/aura_window_capture_machine.cc[diff]
• content/browser/media/capture/aura_window_capture_machine.h[diff]
• content/browser/renderer_host/DEPS[diff]
• content/browser/renderer_host/compositor_impl_android.cc[diff]
• content/browser/renderer_host/delegated_frame_host.cc[diff]
• content/browser/renderer_host/delegated_frame_host.h[diff]
• content/browser/renderer_host/media/video_capture_buffer_pool_unittest.cc[diff]
• content/browser/renderer_host/media/video_capture_controller.cc[diff]
• content/browser/renderer_host/render_widget_host_view_android.cc[diff]
• content/browser/renderer_host/render_widget_host_view_aura.cc[diff]
• content/browser/renderer_host/render_widget_host_view_aura_unittest.cc[diff]
• content/content_browser.gypi[diff]
• content/content_tests.gypi[diff]
• content/test/BUILD.gn[diff]