Enable asynchronous glReadPixels on Windows.

gpu/command_buffer/client/fenced_allocator.cc

 // Copyright (c) 2011 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.
 
 // This file contains the implementation of the FencedAllocator class.
 
 #include "gpu/command_buffer/client/fenced_allocator.h"
 
 #include <algorithm>
 
 #include "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 namespace gpu {
 
 namespace {
 
-// Allocation alignment, must be a power of two.
-const unsigned int kAllocAlignment = 16;
-
 // Round down to the largest multiple of kAllocAlignment no greater than |size|.
 unsigned int RoundDown(unsigned int size) {
-  return size & ~(kAllocAlignment - 1);
+  return size & ~(FencedAllocator::kAllocAlignment - 1);
 }
 
 // Round up to the smallest multiple of kAllocAlignment no smaller than |size|.
 unsigned int RoundUp(unsigned int size) {
-  return (size + (kAllocAlignment - 1)) & ~(kAllocAlignment - 1);
+  return (size + (FencedAllocator::kAllocAlignment - 1)) &
+      ~(FencedAllocator::kAllocAlignment - 1);
 }
 
 }  // namespace
 
 #ifndef _MSC_VER
 const FencedAllocator::Offset FencedAllocator::kInvalidOffset;
+const unsigned int FencedAllocator::kAllocAlignment;
 #endif
 
 FencedAllocator::FencedAllocator(unsigned int size,
                                  CommandBufferHelper* helper,
                                  const base::Closure& poll_callback)
     : helper_(helper),
       poll_callback_(poll_callback),
       bytes_in_use_(0) {
   Block block = { FREE, 0, RoundDown(size), kUnusedToken };
   blocks_.push_back(block);
@@ skipping 200 matching lines @@
 // The blocks are in offset order, so we can do a binary search.
 FencedAllocator::BlockIndex FencedAllocator::GetBlockByOffset(Offset offset) {
   Block templ = { IN_USE, offset, 0, kUnusedToken };
   Container::iterator it = std::lower_bound(blocks_.begin(), blocks_.end(),
                                             templ, OffsetCmp());
   DCHECK(it != blocks_.end() && it->offset == offset);
   return it-blocks_.begin();
 }
 
 }  // namespace gpu