Support jumbo builds in components/viz

Jumbo is a unity build system for Chromium. By combining many cc files
in the same translation unit, the compiler doesn't have to repeat all
the work triggered by shared header. This normally makes building 5-20
times faster.

The downside to jumbo is that code intended to be local to one cc file
suddenly becomes more exposed and might clash with other code.

Jumbo support in components/viz currently saves about 5 CPU minutes of effort,
about 1% of the total reference build effort.

Bug: viz bug
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I7bff566b96b2caeac66aa8e6fb67495231206d51
Commit-Queue: Daniel Bratell <>
Reviewed-by: danakj <>
Cr-Commit-Position: refs/heads/master@{#590954}
4 files changed