cc: Use max_bytes_per_copy_operation setting to determine one-copy flush interval.

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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/renderer/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 160 matching lines @@
   }
 #elif defined(OS_CHROMEOS)
   // Use 512 for high DPI (dsf=2.0f) devices.
   if (widget->screen_info().deviceScaleFactor >= 2.0f)
     default_tile_size = 512;
 #endif
 
   return gfx::Size(default_tile_size, default_tile_size);
 }
 
+size_t GetMaxBytesPerCopyOperation() {

[vmpstr, 2015/06/04 01:26:44]

nit: int this too please 

[reveman, 2015/06/04 02:16:30]

Done.

+  const int kMegabyte = 1024 * 1024;
+
+  // 4MiB is the size of 4 512x512 tiles, which has proven to be a good
+  // default batch size for copy operations.
+  return kMegabyte * 4;
+}
+
 // Check cc::TopControlsState, and blink::WebTopControlsState
 // are kept in sync.
 static_assert(int(blink::WebTopControlsBoth) == int(cc::BOTH),
               "mismatching enums: BOTH");
 static_assert(int(blink::WebTopControlsHidden) == int(cc::HIDDEN),
               "mismatching enums: HIDDEN");
 static_assert(int(blink::WebTopControlsShown) == int(cc::SHOWN),
               "mismatching enums: SHOWN");
 
 static cc::TopControlsState ConvertTopControlsState(
@@ skipping 258 matching lines @@
     settings.create_low_res_tiling = false;
   if (cmd->HasSwitch(cc::switches::kEnableBeginFrameScheduling))
     settings.use_external_begin_frame_source = true;
 
   if (widget_->for_oopif()) {
     // TODO(simonhong): Apply BeginFrame scheduling for OOPIF.
     // See crbug.com/471411.
     settings.use_external_begin_frame_source = false;
   }
 
+  settings.max_bytes_per_copy_operation = GetMaxBytesPerCopyOperation();
+
   scoped_refptr<base::SingleThreadTaskRunner> compositor_thread_task_runner =
       compositor_deps_->GetCompositorImplThreadTaskRunner();
   scoped_refptr<base::SingleThreadTaskRunner>
       main_thread_compositor_task_runner =
           compositor_deps_->GetCompositorMainThreadTaskRunner();
   cc::SharedBitmapManager* shared_bitmap_manager =
       compositor_deps_->GetSharedBitmapManager();
   gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager =
       compositor_deps_->GetGpuMemoryBufferManager();
   cc::TaskGraphRunner* task_graph_runner =
@@ skipping 494 matching lines @@
     return;
   provider->ContextGL()->RateLimitOffscreenContextCHROMIUM();
 }
 
 void RenderWidgetCompositor::SetSurfaceIdNamespace(
     uint32_t surface_id_namespace) {
   layer_tree_host_->set_surface_id_namespace(surface_id_namespace);
 }
 
 }  // namespace content