gpu: Simplify the mapping from BufferFormat to texture type.

gpu/ipc/host/gpu_memory_buffer_support.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/host/gpu_memory_buffer_support.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "gpu/ipc/common/gpu_memory_buffer_support.h"
@@ skipping 15 matching lines @@
       switches::kDisableNativeGpuMemoryBuffers);
 #else
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableNativeGpuMemoryBuffers);
 #endif
 }
 
 GpuMemoryBufferConfigurationSet GetNativeGpuMemoryBufferConfigurations() {
   GpuMemoryBufferConfigurationSet configurations;
 
+#if defined(USE_OZONE) || defined(OS_MACOSX)
   if (AreNativeGpuMemoryBuffersEnabled()) {
     const gfx::BufferFormat kNativeFormats[] = {
         gfx::BufferFormat::R_8,
         gfx::BufferFormat::RG_88,
         gfx::BufferFormat::BGR_565,
         gfx::BufferFormat::RGBA_4444,
         gfx::BufferFormat::RGBA_8888,
         gfx::BufferFormat::BGRA_8888,
         gfx::BufferFormat::UYVY_422,
         gfx::BufferFormat::YVU_420,
         gfx::BufferFormat::YUV_420_BIPLANAR};
     const gfx::BufferUsage kNativeUsages[] = {
         gfx::BufferUsage::GPU_READ, gfx::BufferUsage::SCANOUT,
         gfx::BufferUsage::GPU_READ_CPU_READ_WRITE,
         gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT};
-    for (auto& format : kNativeFormats) {
-      for (auto& usage : kNativeUsages) {
+    for (auto format : kNativeFormats) {
+      for (auto usage : kNativeUsages) {
         if (IsNativeGpuMemoryBufferConfigurationSupported(format, usage))
           configurations.insert(std::make_pair(format, usage));
       }
     }
   }
 
-#if defined(USE_OZONE) || defined(OS_MACOSX)
   // Disable native buffers only when using Mesa.
   bool force_native_gpu_read_write_formats =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kUseGL) != gl::kGLImplementationOSMesaName;
-#else
-  bool force_native_gpu_read_write_formats = false;
-#endif
   if (force_native_gpu_read_write_formats) {
     const gfx::BufferFormat kGPUReadWriteFormats[] = {
         gfx::BufferFormat::BGR_565,   gfx::BufferFormat::RGBA_8888,
         gfx::BufferFormat::RGBX_8888, gfx::BufferFormat::BGRA_8888,
         gfx::BufferFormat::BGRX_8888, gfx::BufferFormat::UYVY_422,
         gfx::BufferFormat::YVU_420,   gfx::BufferFormat::YUV_420_BIPLANAR};
     const gfx::BufferUsage kGPUReadWriteUsages[] = {gfx::BufferUsage::GPU_READ,
                                                     gfx::BufferUsage::SCANOUT};
-    for (auto& format : kGPUReadWriteFormats) {
-      for (auto& usage : kGPUReadWriteUsages) {
+    for (auto format : kGPUReadWriteFormats) {
+      for (auto usage : kGPUReadWriteUsages) {
         if (IsNativeGpuMemoryBufferConfigurationSupported(format, usage))
           configurations.insert(std::make_pair(format, usage));
       }
     }
   }
+#endif  // defined(USE_OZONE) || defined(OS_MACOSX)
 
   return configurations;
 }
 
 uint32_t GetImageTextureTarget(gfx::BufferFormat format,
                                gfx::BufferUsage usage) {
+#if defined(USE_OZONE) || defined(OS_MACOSX)
   GpuMemoryBufferConfigurationSet native_configurations =
       GetNativeGpuMemoryBufferConfigurations();
   if (native_configurations.find(std::make_pair(format, usage)) ==
       native_configurations.end()) {
     return GL_TEXTURE_2D;
   }
 
   switch (GetNativeGpuMemoryBufferType()) {
     case gfx::OZONE_NATIVE_PIXMAP:
       // GPU memory buffers that are shared with the GL using EGLImages
       // require TEXTURE_EXTERNAL_OES.
       return GL_TEXTURE_EXTERNAL_OES;
     case gfx::IO_SURFACE_BUFFER:
       // IOSurface backed images require GL_TEXTURE_RECTANGLE_ARB.
       return GL_TEXTURE_RECTANGLE_ARB;
     case gfx::SHARED_MEMORY_BUFFER:
-      return GL_TEXTURE_2D;
     case gfx::EMPTY_BUFFER:
-      NOTREACHED();
-      return GL_TEXTURE_2D;
+      break;
   }
-
   NOTREACHED();
   return GL_TEXTURE_2D;
+#else  // defined(USE_OZONE) || defined(OS_MACOSX)
+  return GL_TEXTURE_2D;
+#endif
 }
 
 }  // namespace gpu