Austin Eng 09c308cfcf Improve ScopedEnvironmentVar to distinguish between null and empty ... Found while investigating Swiftshader support. Some Vulkan loaders fail to create an instance if VK_ICD_FILENAMES is empty string rather than entirely absent. It was set to empty string because Dawn did not distinguish between nonexistent environment variables and the empty string. This CL adds distinguishing between the two, including tests for the behavior. Bug: chromium:1266550 Change-Id: I1680a281f62e6b340009e01da65db9d485e2975e Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/69520 Auto-Submit: Austin Eng <enga@chromium.org> Reviewed-by: Loko Kung <lokokung@google.com> Commit-Queue: Austin Eng <enga@chromium.org>		2021-11-16 23:37:15 +00:00
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Animometer.cpp	Remove several compile-time constants in favor of limits	2021-10-13 18:57:18 +00:00
BUILD.gn	Autoformat all tests and examples	2020-07-10 20:33:08 +00:00
CHelloTriangle.cpp	Remove deprecated RenderPass*Attachment.attachment	2021-09-14 10:42:22 +00:00
CMakeLists.txt	Add initial CMakeLists.txt files	2020-02-05 17:16:05 +00:00
ComputeBoids.cpp	wgpu::InputStepMode -> VertexStepMode	2021-07-25 18:40:19 +00:00
CppHelloTriangle.cpp	Update deprecated TextureUsage flag names	2021-08-10 04:07:37 +00:00
CubeReflection.cpp	Add scoped autoreleasepool to tests and examples	2021-06-24 19:21:31 +00:00
ManualSwapChainTest.cpp	Add scoped autoreleasepool to tests and examples	2021-06-24 19:21:31 +00:00
OWNERS	Add more / finer-grained OWNERS	2021-11-02 09:30:52 +00:00
SampleUtils.cpp	Improve ScopedEnvironmentVar to distinguish between null and empty	2021-11-16 23:37:15 +00:00
SampleUtils.h	Make examples and utils use webgpu.h	2019-10-25 11:36:47 +00:00