Expand is_linux to is_linux || is_chromeos.

Currently is_linux GN variable is set to true on Chrome OS build,
but is is planned to set false. This is the preparation to
keep the compatibility.

Bug: chromium:1110266
Test: Built locally.
Change-Id: I87e8f1312c85f85a3f882698f1dce3d65e0cfab6
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/48348
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Hidehiko Abe <hidehiko@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 8ff1631..03c30e9 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -134,7 +134,7 @@
       ]
     }
 
-    if (is_linux) {
+    if (is_linux || is_chromeos) {
       ldflags = [ "-Wl,--gc-sections" ]
 
       if (current_cpu == "mipsel") {
diff --git a/src/OpenGL/compiler/BUILD.gn b/src/OpenGL/compiler/BUILD.gn
index ea72f32..67b2739 100644
--- a/src/OpenGL/compiler/BUILD.gn
+++ b/src/OpenGL/compiler/BUILD.gn
@@ -76,7 +76,7 @@
     all_dependent_configs = [ ":swiftshader_translator_disable_pool_alloc" ]
   }
 
-  if (is_linux || is_mac || is_fuchsia) {
+  if (is_linux || is_chromeos || is_mac || is_fuchsia) {
     sources += [ "ossource_posix.cpp" ]
   } else if (is_win) {
     sources += [ "ossource_win.cpp" ]
diff --git a/src/OpenGL/libEGL/BUILD.gn b/src/OpenGL/libEGL/BUILD.gn
index 602badd..436ced3 100644
--- a/src/OpenGL/libEGL/BUILD.gn
+++ b/src/OpenGL/libEGL/BUILD.gn
@@ -80,7 +80,7 @@
       "-Wl,-exported_symbols_list," +
           rebase_path("libEGL.exports", root_build_dir),
     ]
-  } else if (is_linux) {
+  } else if (is_linux || is_chromeos) {
     if (use_x11) {
       sources += [ "../../Main/libX11.cpp" ]
     }
diff --git a/src/OpenGL/libGLESv2/BUILD.gn b/src/OpenGL/libGLESv2/BUILD.gn
index da2af9e..8d55199 100644
--- a/src/OpenGL/libGLESv2/BUILD.gn
+++ b/src/OpenGL/libGLESv2/BUILD.gn
@@ -130,7 +130,7 @@
       "-Wl,-exported_symbols_list," +
           rebase_path("libGLESv2.exports", root_build_dir),
     ]
-  } else if (is_linux) {
+  } else if (is_linux || is_chromeos) {
     inputs = [ "libGLESv2.lds" ]
     ldflags = [ "-Wl,--version-script=" +
                 rebase_path("libGLESv2.lds", root_build_dir) ]
diff --git a/src/Reactor/BUILD.gn b/src/Reactor/BUILD.gn
index 5a5eec1..cc24a3e 100644
--- a/src/Reactor/BUILD.gn
+++ b/src/Reactor/BUILD.gn
@@ -19,7 +19,7 @@
   # PPC64.
   use_swiftshader_with_subzero =
       current_cpu != "arm64" && current_cpu != "mips64el" && current_cpu != "ppc64"
-  supports_llvm = is_linux || is_fuchsia || is_win || is_android || is_mac
+  supports_llvm = is_linux || is_chromeos || is_fuchsia || is_win || is_android || is_mac
 }
 
 config("swiftshader_reactor_private_config") {
@@ -102,7 +102,7 @@
     if (is_win) {
       include_dirs +=
           [ "../../third_party/llvm-subzero/build/Windows/include/" ]
-    } else if (is_linux) {
+    } else if (is_linux || is_chromeos) {
       include_dirs += [ "../../third_party/llvm-subzero/build/Linux/include/" ]
     } else if (is_fuchsia) {
       include_dirs +=
@@ -143,7 +143,7 @@
           cflags += [ "-Wno-sign-compare" ]
         }
       }
-    } else if (is_linux || is_mac || is_fuchsia) {
+    } else if (is_linux || is_chromeos || is_mac || is_fuchsia) {
       cflags += [ "-Wno-macro-redefined" ]
     }
 
@@ -339,7 +339,7 @@
       "$llvm_dir/configs/common/include/",
     ]
 
-    if (is_linux) {
+    if (is_linux || is_chromeos) {
       include_dirs += [ "$llvm_dir/configs/linux/include/" ]
     } else if (is_fuchsia) {
       include_dirs += [ "$llvm_dir/configs/fuchsia/include/" ]
diff --git a/src/System/BUILD.gn b/src/System/BUILD.gn
index 4595028..b614529 100644
--- a/src/System/BUILD.gn
+++ b/src/System/BUILD.gn
@@ -28,7 +28,7 @@
     "Socket.hpp",
     "Timer.hpp",
   ]
-  if (is_linux || is_android) {
+  if (is_linux || is_chromeos || is_android) {
     sources += [
       "Linux/MemFd.hpp",
     ]
@@ -46,7 +46,7 @@
     "Memory.cpp",
     "Timer.cpp",
   ]
-  if (is_linux || is_android) {
+  if (is_linux || is_chromeos || is_android) {
     sources += [
       "Linux/MemFd.cpp",
     ]
diff --git a/src/Vulkan/BUILD.gn b/src/Vulkan/BUILD.gn
index c3f503b..a8d0765 100644
--- a/src/Vulkan/BUILD.gn
+++ b/src/Vulkan/BUILD.gn
@@ -18,7 +18,7 @@
 
 # Need a separate config to ensure the warnings are added to the end.
 config("swiftshader_libvulkan_private_config") {
-  if (is_linux) {
+  if (is_linux || is_chromeos) {
     defines = [
       "VK_USE_PLATFORM_XLIB_KHR",
       "VK_USE_PLATFORM_XCB_KHR",
@@ -96,7 +96,7 @@
     "VkStringify.hpp",
     "VulkanPlatform.hpp",
   ]
-  if (is_linux || is_android) {
+  if (is_linux || is_chromeos || is_android) {
     sources += [
       "VkDeviceMemoryExternalLinux.hpp",
       "VkSemaphoreExternalLinux.hpp",
@@ -161,7 +161,7 @@
       "-Wl,-exported_symbols_list," +
           rebase_path("vk_swiftshader.exports", root_build_dir),
     ]
-  } else if (is_linux || is_fuchsia) {
+  } else if (is_linux || is_chromeos || is_fuchsia) {
     inputs = [
       "vk_swiftshader.lds",
     ]
diff --git a/src/WSI/BUILD.gn b/src/WSI/BUILD.gn
index b544fef..fa37f94 100644
--- a/src/WSI/BUILD.gn
+++ b/src/WSI/BUILD.gn
@@ -31,7 +31,7 @@
     "VkSwapchainKHR.hpp",
   ]
 
-  if (is_linux) {
+  if (is_linux || is_chromeos) {
     sources += [
       "XcbSurfaceKHR.cpp",
       "XcbSurfaceKHR.hpp",
diff --git a/third_party/llvm-10.0/BUILD.gn b/third_party/llvm-10.0/BUILD.gn
index a876a0b..70e14c0 100644
--- a/third_party/llvm-10.0/BUILD.gn
+++ b/third_party/llvm-10.0/BUILD.gn
@@ -98,7 +98,7 @@
   "configs/common/lib/Transforms/InstCombine/",
 ]
 
-if (is_linux) {
+if (is_linux || is_chromeos) {
   llvm_include_dirs += [ "configs/linux/include/" ]
 } else if (is_fuchsia) {
   llvm_include_dirs += [ "configs/fuchsia/include/" ]