Refactor OS_LINUX preprocessor directive for LaCrOS effort.

Currently, ChromeOS defines the OS_LINUX directive as well as
OS_CHROMEOS.  We're working to separate these two, so we're
making the fact that OS_LINUX == OS_LINUX || OS_CHROMEOS
explicit.

This is changes for /gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc

This CL was uploaded by git cl split.

R=dcastagna@chromium.org

Bug: 1110266
Change-Id: I59878d4ecbedf46659a65b383efdcbd5b4b3d08f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2370300Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Sean McAllister <smcallis@google.com>
Cr-Commit-Position: refs/heads/master@{#801365}

gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc

@@ -29,7 +29,7 @@
 #include "ui/gl/gl_image.h"
 #include "ui/gl/test/gl_image_test_support.h"
 
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
 #include "gpu/ipc/common/gpu_memory_buffer_impl_native_pixmap.h"
 #include "ui/gfx/linux/client_native_pixmap_factory_dmabuf.h"
 #endif
@@ -72,7 +72,7 @@ class GpuMemoryBufferTest : public testing::TestWithParam<gfx::BufferFormat> {
   GLManager gl_;
 };
 
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
 class GpuMemoryBufferTestEGL : public testing::Test,
                                public gpu::GpuCommandBufferTestEGL {
  public:
@@ -90,7 +90,7 @@ class GpuMemoryBufferTestEGL : public testing::Test,
   bool egl_initialized_{false};
   std::unique_ptr<gfx::ClientNativePixmapFactory> native_pixmap_factory_;
 };
-#endif  // defined(OS_LINUX)
+#endif  // defined(OS_LINUX) || defined(OS_CHROMEOS)
 
 namespace {
 
@@ -361,7 +361,7 @@ TEST_P(GpuMemoryBufferTest, Lifecycle) {
   glDeleteTextures(1, &texture_id);
 }
 
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
 // Test glCreateImageCHROMIUM with gfx::NATIVE_PIXMAP. Basically the test
 // reproduces the situation where some dmabuf fds are available outside the
 // gpu process and the user wants to import them using glCreateImageCHROMIUM.
@@ -475,7 +475,7 @@ TEST_F(GpuMemoryBufferTestEGL, GLCreateImageCHROMIUMFromNativePixmap) {
   glDestroyImageCHROMIUM(image_id);
   glDeleteTextures(1, &texture_id);
 }
-#endif  // defined(OS_LINUX)
+#endif  // defined(OS_LINUX) || defined(OS_CHROMEOS)
 
 INSTANTIATE_TEST_SUITE_P(
     GpuMemoryBufferTests,