content: Reduce number of raster threads on big.LITTLE.

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 <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 143 matching lines @@
   DCHECK(index < arraysize(kGpuFeatureInfo));
   *eof = (index == arraysize(kGpuFeatureInfo) - 1);
   return kGpuFeatureInfo[index];
 }
 
 }  // namespace
 
 int NumberOfRendererRasterThreads() {
   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.
+#if defined(OS_ANDROID) || \
+    (defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY))
+  // Android and ChromeOS ARM devices 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;
 
 #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;
@@ skipping 229 matching lines @@
     }
   }
   return problem_list;
 }
 
 std::vector<std::string> GetDriverBugWorkarounds() {
   return GpuDataManagerImpl::GetInstance()->GetDriverBugWorkarounds();
 }
 
 }  // namespace content