cc: one copy is default as well as final fallback.

content/browser/gpu/compositor_util.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 "content/browser/gpu/compositor_util.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 173 matching lines @@
   int num_processors = base::SysInfo::NumberOfProcessors();
 
 #if defined(OS_ANDROID)
   // Android may report 6 to 8 CPUs for big.LITTLE configurations.
   // Limit the number of raster threads based on maximum of 4 big cores.
   num_processors = std::min(num_processors, 4);
 #endif
 
   int num_raster_threads = num_processors / 2;
 
-  // Async uploads is used when neither zero-copy nor one-copy is enabled and
-  // it uses its own thread, so reduce the number of raster threads when async
-  // uploads is in use.
-  bool async_uploads_is_used =
-      !IsZeroCopyUploadEnabled() && !IsOneCopyUploadEnabled();
-  if (async_uploads_is_used)
-    --num_raster_threads;
-
 #if defined(OS_ANDROID)
   // Limit the number of raster threads to 1 on Android.
   // TODO(reveman): Remove this when we have a better mechanims to prevent
   // pre-paint raster work from slowing down non-raster work. crbug.com/504515
   num_raster_threads = 1;
 #endif
 
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kNumRasterThreads)) {
     std::string string_value = command_line.GetSwitchValueASCII(
         switches::kNumRasterThreads);
     if (!base::StringToInt(string_value, &num_raster_threads)) {
       DLOG(WARNING) << "Failed to parse switch " <<
           switches::kNumRasterThreads  << ": " << string_value;
     }
   }
 
   return cc::MathUtil::ClampToRange(num_raster_threads, kMinRasterThreads,
                                     kMaxRasterThreads);
 }
 
-bool IsOneCopyUploadEnabled() {
-  if (IsZeroCopyUploadEnabled())
-    return false;
-
-  const base::CommandLine& command_line =
-      *base::CommandLine::ForCurrentProcess();
-  return !command_line.HasSwitch(switches::kDisableOneCopy);
-}
-
 bool IsZeroCopyUploadEnabled() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
   // Single-threaded mode in the renderer process (for layout tests) is
   // synchronous, which depends on tiles being ready to draw when raster is
   // complete.  Therefore, it must use one of zero copy, software raster, or
   // GPU raster. So we force zero-copy on for the case where software/GPU raster
   // is not used.
   // TODO(reveman): One-copy can work with sync compositing: crbug.com/490295.
   if (command_line.HasSwitch(switches::kDisableThreadedCompositing))
@@ skipping 165 matching lines @@
     }
   }
   return problem_list;
 }
 
 std::vector<std::string> GetDriverBugWorkarounds() {
   return GpuDataManagerImpl::GetInstance()->GetDriverBugWorkarounds();
 }
 
 }  // namespace content