Zero-init Dawn structs

Needed for https://dawn-review.googlesource.com/c/dawn/+/24622
and https://dawn-review.googlesource.com/c/dawn/+/24620

Bug: none, dawn:22
Change-Id: I22e6dd8d695060f01e29d9c9c51e03233c0a6ef7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2292833
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#787462}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 7c71626bdc4358c8ce07ea54c3d0672e8e78a509
diff --git a/command_buffer/service/shared_image_backing_factory_d3d_unittest.cc b/command_buffer/service/shared_image_backing_factory_d3d_unittest.cc
index 6e0528f..e6bcb27 100644
--- a/command_buffer/service/shared_image_backing_factory_d3d_unittest.cc
+++ b/command_buffer/service/shared_image_backing_factory_d3d_unittest.cc
@@ -571,7 +571,7 @@
     color_desc.storeOp = wgpu::StoreOp::Store;
     color_desc.clearColor = {0, 255, 0, 255};
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
@@ -686,7 +686,7 @@
     color_desc.loadOp = wgpu::LoadOp::Load;
     color_desc.storeOp = wgpu::StoreOp::Store;
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
@@ -771,7 +771,7 @@
     color_desc.storeOp = wgpu::StoreOp::Clear;
     color_desc.clearColor = {0, 255, 0, 255};
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
diff --git a/command_buffer/service/shared_image_backing_factory_iosurface_unittest.cc b/command_buffer/service/shared_image_backing_factory_iosurface_unittest.cc
index 931fda3..dc91ca1 100644
--- a/command_buffer/service/shared_image_backing_factory_iosurface_unittest.cc
+++ b/command_buffer/service/shared_image_backing_factory_iosurface_unittest.cc
@@ -408,7 +408,7 @@
     color_desc.storeOp = wgpu::StoreOp::Store;
     color_desc.clearColor = {0, 255, 0, 255};
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
@@ -529,7 +529,7 @@
     color_desc.loadOp = wgpu::LoadOp::Load;
     color_desc.storeOp = wgpu::StoreOp::Store;
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
@@ -611,7 +611,7 @@
     color_desc.storeOp = wgpu::StoreOp::Clear;
     color_desc.clearColor = {0, 255, 0, 255};
 
-    wgpu::RenderPassDescriptor renderPassDesc;
+    wgpu::RenderPassDescriptor renderPassDesc = {};
     renderPassDesc.colorAttachmentCount = 1;
     renderPassDesc.colorAttachments = &color_desc;
     renderPassDesc.depthStencilAttachment = nullptr;
diff --git a/command_buffer/tests/shared_image_gl_backing_produce_dawn_unittest.cc b/command_buffer/tests/shared_image_gl_backing_produce_dawn_unittest.cc
index bbb2e41..1ca1c48 100644
--- a/command_buffer/tests/shared_image_gl_backing_produce_dawn_unittest.cc
+++ b/command_buffer/tests/shared_image_gl_backing_produce_dawn_unittest.cc
@@ -156,13 +156,12 @@
     buffer_desc.usage = wgpu::BufferUsage::MapRead | wgpu::BufferUsage::CopyDst;
     wgpu::Buffer readback_buffer = device.CreateBuffer(&buffer_desc);
 
-    wgpu::TextureCopyView copy_src;
+    wgpu::TextureCopyView copy_src = {};
     copy_src.texture = texture;
     copy_src.mipLevel = 0;
-    copy_src.arrayLayer = 0;
     copy_src.origin = {0, 0, 0};
 
-    wgpu::BufferCopyView copy_dst;
+    wgpu::BufferCopyView copy_dst = {};
     copy_dst.buffer = readback_buffer;
     copy_dst.offset = 0;
     copy_dst.bytesPerRow = 256;
diff --git a/command_buffer/tests/webgpu_mailbox_unittest.cc b/command_buffer/tests/webgpu_mailbox_unittest.cc
index 92c6e34..150dbf3 100644
--- a/command_buffer/tests/webgpu_mailbox_unittest.cc
+++ b/command_buffer/tests/webgpu_mailbox_unittest.cc
@@ -106,17 +106,15 @@
     wgpu::Texture texture = wgpu::Texture::Acquire(reservation.texture);
 
     // Clear the texture using a render pass.
-    wgpu::RenderPassColorAttachmentDescriptor color_desc;
+    wgpu::RenderPassColorAttachmentDescriptor color_desc = {};
     color_desc.attachment = texture.CreateView();
-    color_desc.resolveTarget = nullptr;
     color_desc.loadOp = wgpu::LoadOp::Clear;
     color_desc.storeOp = wgpu::StoreOp::Store;
     color_desc.clearColor = {0, 255, 0, 255};
 
-    wgpu::RenderPassDescriptor render_pass_desc;
+    wgpu::RenderPassDescriptor render_pass_desc = {};
     render_pass_desc.colorAttachmentCount = 1;
     render_pass_desc.colorAttachments = &color_desc;
-    render_pass_desc.depthStencilAttachment = nullptr;
 
     wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
     wgpu::RenderPassEncoder pass = encoder.BeginRenderPass(&render_pass_desc);
@@ -147,13 +145,12 @@
     buffer_desc.usage = wgpu::BufferUsage::MapRead | wgpu::BufferUsage::CopyDst;
     wgpu::Buffer readback_buffer = device.CreateBuffer(&buffer_desc);
 
-    wgpu::TextureCopyView copy_src;
+    wgpu::TextureCopyView copy_src = {};
     copy_src.texture = texture;
     copy_src.mipLevel = 0;
-    copy_src.arrayLayer = 0;
     copy_src.origin = {0, 0, 0};
 
-    wgpu::BufferCopyView copy_dst;
+    wgpu::BufferCopyView copy_dst = {};
     copy_dst.buffer = readback_buffer;
     copy_dst.offset = 0;
     copy_dst.bytesPerRow = 256;