Use GpuPreferences to avoid directly accessing switches in gpu related code

gpu/command_buffer/service/gpu_preferences.h

Index: gpu/command_buffer/service/gpu_preferences.h
diff --git a/gpu/command_buffer/service/gpu_preferences.h b/gpu/command_buffer/service/gpu_preferences.h
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+// 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.
+
+#ifndef GPU_PREFERENCES_H_
+#define GPU_PREFERENCES_H_
+
+#include <stddef.h>
+
+#include <set>
+
+#include "base/macros.h"
+#include "build/build_config.h"
+#include "gpu/command_buffer/common/constants.h"
+
+namespace base {
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+};
+
+namespace gpu {
+
+struct GpuPreferences {
+  // Prioritizes the UI's command stream in the GPU process
+  bool ui_prioritize_in_gpu_process = false;
+
+  // Turn off gpu program caching
+  bool disable_gpu_program_cahce = false;
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // Fall back to using CAOpenGLLayers display content, instead of the IOSurface
+  // based overlay display path.
+  bool disable_mac_overlays = false;
+
+  // Disable use of cross-process CALayers to display content directly from the
+  // GPU process on Mac.
+  bool disable_remote_core_animation = false;
+
+  // Show borders around CALayers corresponding to overlays and partial damage.
+  bool show_mac_overlays_borders = false;
+#endif
+
+
+#if defined(OS_CHROMEOS)
+  // Disables VA-API accelerated video encode.
+  bool disable_vaapi_accelerated_video_encode = false;
+#endif
+
+  // Disables use of D3D11.
+  bool disable_d3d11 = false;
+
+  // Stop the GPU from synchronizing on the vsync before presenting.
+  // We can select from the options below:
+  //  beginframe : Next frame can start without any delay on cc::scheduler.
+  //  gpu : Disable gpu vsync.
+  //  default: Set both flags.
+  bool disable_gpu_vsync = false;
+
+  // Turns on GPU logging (debug build only).
+  bool enable_gpu_service_logging = false;
+
+  // Turns on calling TRACE for every GL call.
+  bool enable_gpu_service_tracing = false;
+
+  // Runs the renderer and plugins in the same process as the browser.
+  bool single_process = false;
+
+  // Run the GPU process as a thread in the browser process.
+  bool in_process_gpu = false;
+
+  // Ignores GPU blacklist.
+  bool ignore_gpu_black_list = false;
+
+  // Disable hardware acceleration of mjpeg decode for captured frame, where
+  // available.
+  bool disable_accelerated_mjpeg_decode = false;
+
+  // Disables hardware acceleration of video decode, where available.
+  bool disable_accelerated_video_decode = false;
+
+  // Enables experimental hardware acceleration for VP8/VP9 video decoding.
+  bool enable_accelerated_vpx_decode = false;
+
+  // ===================================
+  // settings from //gpu/config/gpu_switches.h
+  std::set<int> gpu_driver_bug_workarounds;
+
+  // ===================================
+  // settings from //gpu/command_buffer/service/gpu_switches.cc
+
+  // Always return success when compiling a shader. Linking will still fail.
+  bool compile_shader_always_succeeds = false;
+
+  // Disable the GL error log limit.
+  bool disable_gl_error_limit = false;
+
+  // Disable the GLSL translator.
+  bool disable_glsl_translator = false;
+
+  // Disable workarounds for various GPU driver bugs.
+  bool disable_gpu_driver_bug_workarounds = false;
+
+  // Turn off user-defined name hashing in shaders.
+  bool disable_shader_name_hashing = false;
+
+  // Turn on Logging GPU commands.
+  bool enable_gpu_command_logging = false;
+
+  // Turn on Calling GL Error after every command.
+  bool enable_gpu_debugging = false;
+
+  // Enable GPU service logging.
+  bool enable_gpu_service_logging_gpu = false;
+
+  // Turn off gpu program caching
+  bool disable_gpu_program_cache = false;
+
+  // Enforce GL minimums.
+  bool enforce_gl_minimums = false;
+
+  // Sets the total amount of memory that may be allocated for GPU resources
+  size_t force_gpu_mem_available = 0;
+
+  // Sets the maximum size of the in-memory gpu program cache, in kb
+  size_t gpu_program_cache_size = kDefaultMaxProgramCacheMemoryBytes;
+
+  // Disables the GPU shader on disk cache.
+  bool disable_gpu_shader_disk_cache = false;
+
+  // Allows async texture uploads (off main thread) via GL context sharing.
+  bool enable_share_group_async_texture_upload = false;
+
+  // Enable WebGL subscribe uniform extension.
+  bool enable_subscribe_uniform_extension = false;
+
+  // Simulates shared textures when share groups are not available.
+  // Not available everywhere.
+  bool enable_threaded_texture_mailboxes = false;
+
+  // Include ANGLE's intermediate representation (AST) output in shader
+  // compilation info logs.
+  bool gl_shader_interm_output = false;
+
+  // Emulate ESSL lowp and mediump float precisions by mutating the shaders to
+  // round intermediate values in ANGLE.
+  bool emulate_shader_precision = false;
+
+  // Enables using path rendering implementation implemented currently
+  // in NV_path_rendering OpenGL extension. Requires compatible hardware
+  // and driver. This is used in GPU rasterization.
+  bool enable_gl_path_rendering = false;
+
+  // ===================================
+  // settings from //ui/gl/gl_switches.h
+  bool enable_unsafe_es3_apis = false;
+
+  static GpuPreferences* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<GpuPreferences>;
+
+  GpuPreferences();
+  ~GpuPreferences();
+
+  DISALLOW_COPY_AND_ASSIGN(GpuPreferences);
+};
+
+}  // namespace gpu
+
+#endif // GPU_PREFERENCES_H_