gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/gles2_implementation.cc

Index: gpu/command_buffer/client/gles2_implementation.cc
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index b0efc3769da617acfcc5423f07951c6f8d1dc208..83ae1c75dc8e10083f99dd9efc031d88fe2ff334 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -155,14 +155,29 @@ bool GLES2Implementation::Initialize(
     return false;
   }
 
-  mapped_memory_.reset(new MappedMemoryManager(helper_, mapped_memory_limit));
-
+  MappedMemoryManagerSettings mapped_memory_settings;
+  mapped_memory_settings.unused_memory_reclaim_limit =
+      mapped_memory_limit;
+  mapped_memory_settings.aggressive_reuse = false;
+  mapped_memory_.reset(new MappedMemoryManager(
+      helper_, mapped_memory_settings));
+
+  MappedMemoryManagerSettings transfer_buffer_memory_settings;
+  transfer_buffer_memory_settings.unused_memory_reclaim_limit =
+      mapped_memory_limit;
+  transfer_buffer_memory_settings.aggressive_reuse = true;
+  transfer_buffer_memory_.reset(new MappedMemoryManager(
+      helper_, transfer_buffer_memory_settings));
+
+  // Set the chunk size of transfer buffer chunks. Let the generic memory
+  // manager allocate chunks to be as small as possible, i.e. the default size
+  // multiple 1.
   unsigned chunk_size = 2 * 1024 * 1024;
   if (mapped_memory_limit != kNoLimit) {
     // Use smaller chunks if the client is very memory conscientious.
     chunk_size = std::min(mapped_memory_limit / 4, chunk_size);
   }
-  mapped_memory_->set_chunk_size_multiple(chunk_size);
+  transfer_buffer_memory_->set_chunk_size_multiple(chunk_size);
 
   if (!QueryAndCacheStaticState())
     return false;
@@ -177,7 +192,7 @@ bool GLES2Implementation::Initialize(
           static_state_.int_state.max_combined_texture_image_units]);
 
   query_tracker_.reset(new QueryTracker(mapped_memory_.get()));
-  buffer_tracker_.reset(new BufferTracker(mapped_memory_.get()));
+  buffer_tracker_.reset(new BufferTracker(transfer_buffer_memory_.get()));
   gpu_memory_buffer_tracker_.reset(new GpuMemoryBufferTracker(gpu_control_));
 
 #if defined(GLES2_SUPPORT_CLIENT_SIDE_ARRAYS)
@@ -304,6 +319,7 @@ uint32 GLES2Implementation::GetResultShmOffset() {
 
 void GLES2Implementation::FreeUnusedSharedMemory() {
   mapped_memory_->FreeUnused();
+  transfer_buffer_memory_->FreeUnused();
 }
 
 void GLES2Implementation::FreeEverything() {