It should be possible to do this efficiently now that we have render surface caching. The idea is:

- Add a new layer flag to enable trilinear filtering.
- Layers with trilinear filtering will require a render surface.
- GenerateMipmap will be called after updating the render surface.
- GLRenderer will use GL_LINEAR_MIPMAP_LINEAR when drawing the render surface.
- Chrome OS UI can enable render surface caching to avoid unnecessary updates of render surface and calls to GenerateMipmap.

Created a short document to describe this problem and the solution in more detail: https://docs.google.com/a/google.com/document/d/1jxo-80UX2tSatReRKg1RYuOgVnLxE3msi3cVoKnjps4/edit?usp=sharing

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0d133634f10cc828d8f7d45dbeef628e94d908d1

commit 0d133634f10cc828d8f7d45dbeef628e94d908d1
Author: David Reveman <reveman@chromium.org>
Date: Tue Sep 12 17:05:40 2017

cc: Add trilinear filtering support.

This adds trilinear filtering support to layers. All layers with this
type of filtering a rendered to a render surface and mipmaps are
generated for the render surface when supported by renderer.

This allows for more efficient and higher quality down-sampling.
It can provide a significant performance improvement when combined
with render surface caching.

BUG=757020
TEST=cc_unittests --gtest_also_run_disabled_tests --use-gpu-in-tests --gtest_filter=GLRendererPixelTest.DISABLED_TrilinearFiltering

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I14eb1b06231c9732651670f0cd4b95f95344f5b2
Reviewed-on: https://chromium-review.googlesource.com/621540
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501318}
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/ipc/cc_param_traits.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/ipc/cc_param_traits_unittest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/ipc/cc_serialization_perftest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer_impl.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer_impl.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer_impl_test_properties.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/layer_impl_test_properties.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/render_surface_impl.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/layers/render_surface_impl.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/output/direct_renderer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/output/direct_renderer.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/output/renderer_pixeltest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/output/software_renderer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/output/software_renderer.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/quads/render_pass.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/quads/render_pass.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/quads/render_pass_unittest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/resources/resource_provider.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/resources/resource_provider.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/resources/scoped_resource.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/resources/scoped_resource.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/trees/effect_node.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/trees/effect_node.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/trees/layer_tree_host_common_unittest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/cc/trees/property_tree_builder.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/service/display/gl_renderer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/service/display/gl_renderer.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/service/display/skia_renderer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/service/display/skia_renderer.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/service/display/surface_aggregator.cc
[add] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/components/viz/test/data/trilinear_filtering.png
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/gpu/command_buffer/common/capabilities.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/gpu/command_buffer/service/gles2_cmd_decoder.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/gpu/ipc/common/gpu_command_buffer_traits_multi.h
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/services/viz/public/cpp/compositing/struct_traits_unittest.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/ui/compositor/layer.cc
[modify] https://crrev.com/0d133634f10cc828d8f7d45dbeef628e94d908d1/ui/compositor/layer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cefe5557b34e3cb4723508c9856d8fd964de9f26

commit cefe5557b34e3cb4723508c9856d8fd964de9f26
Author: David Reveman <reveman@chromium.org>
Date: Wed Sep 13 17:59:28 2017

viz: Add generate_mipmap to render_pass.mojom.

Trilinear filtering support that landed recently uses this.

BUG=757020
TEST=services_unittests --gtest_filter=StructTraitsTest.RenderPass

Change-Id: Iaa5f00b619f385f313aabf858e9f2309d67c7fdf
Reviewed-on: https://chromium-review.googlesource.com/665060
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501687}
[modify] https://crrev.com/cefe5557b34e3cb4723508c9856d8fd964de9f26/services/viz/public/cpp/compositing/render_pass_struct_traits.cc
[modify] https://crrev.com/cefe5557b34e3cb4723508c9856d8fd964de9f26/services/viz/public/cpp/compositing/render_pass_struct_traits.h
[modify] https://crrev.com/cefe5557b34e3cb4723508c9856d8fd964de9f26/services/viz/public/cpp/compositing/struct_traits_unittest.cc
[modify] https://crrev.com/cefe5557b34e3cb4723508c9856d8fd964de9f26/services/viz/public/interfaces/compositing/render_pass.mojom

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b5f7b1f9b9adb4c34dfc9611917e2a92df1fddda

commit b5f7b1f9b9adb4c34dfc9611917e2a92df1fddda
Author: David Reveman <reveman@chromium.org>
Date: Wed Jan 17 01:59:33 2018

viz: Use valid color space for TrilinearFiltering test.

This was causing a DCHECK to fail in debug builds.

Bug: 757020
Test: viz_unittests --gtest_also_run_disabled_tests --use-gpu-in-tests --gtest_filter=GLRendererPixelTest.DISABLED_TrilinearFiltering
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: I11394b57f594142fc57f3fff52e5e5b1737ed889
Reviewed-on: https://chromium-review.googlesource.com/868178
Commit-Queue: David Reveman <reveman@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529542}
[modify] https://crrev.com/b5f7b1f9b9adb4c34dfc9611917e2a92df1fddda/components/viz/service/display/renderer_pixeltest.cc