Use GpuPreferences to avoid directly accessing switches in gpu related code

gpu/command_buffer/service/memory_program_cache_unittest.cc

 // Copyright (c) 2012 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/command_buffer/service/memory_program_cache.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/bind.h"
@@ skipping 49 matching lines @@
 
  private:
   GLsizei length_;
   GLenum format_;
   const char* binary_;
 };
 
 class MemoryProgramCacheTest : public GpuServiceTest {
  public:
   static const size_t kCacheSizeBytes = 1024;
+  static const bool kDisableGpuDiskCache = false;
   static const GLuint kVertexShaderClientId = 90;
   static const GLuint kVertexShaderServiceId = 100;
   static const GLuint kFragmentShaderClientId = 91;
   static const GLuint kFragmentShaderServiceId = 100;
 
   MemoryProgramCacheTest()
-      : cache_(new MemoryProgramCache(kCacheSizeBytes)),
+      : cache_(new MemoryProgramCache(kCacheSizeBytes, kDisableGpuDiskCache)),
         vertex_shader_(NULL),
         fragment_shader_(NULL),
-        shader_cache_count_(0) { }
+        shader_cache_count_(0) {
+  }
   ~MemoryProgramCacheTest() override { shader_manager_.Destroy(false); }
 
   void ShaderCacheCb(const std::string& key, const std::string& shader) {
     shader_cache_count_++;
     shader_cache_shader_ = shader;
   }
 
   int32_t shader_cache_count() { return shader_cache_count_; }
   const std::string& shader_cache_shader() { return shader_cache_shader_; }
 
@@ skipping 590 matching lines @@
       fragment_shader_,
       NULL,
       varyings_,
       GL_NONE,
       base::Bind(&MemoryProgramCacheTest::ShaderCacheCb,
                  base::Unretained(this))));
 }
 
 }  // namespace gles2
 }  // namespace gpu