gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/buffer_tracker.cc

Index: gpu/command_buffer/client/buffer_tracker.cc
diff --git a/gpu/command_buffer/client/buffer_tracker.cc b/gpu/command_buffer/client/buffer_tracker.cc
index 18cedb975d059664d421d5e65f11a982a39a474b..0d6a1372a2a23ba77daf13890a3405db1be7522f 100644
--- a/gpu/command_buffer/client/buffer_tracker.cc
+++ b/gpu/command_buffer/client/buffer_tracker.cc
@@ -42,6 +42,13 @@ BufferTracker::Buffer* BufferTracker::GetBuffer(GLuint client_id) {
   return it != buffers_.end() ? it->second : NULL;
 }
 
+void BufferTracker::UnmanageBuffer(GLuint client_id) {
+  BufferMap::iterator it = buffers_.find(client_id);
+  if (it == buffers_.end())
+    return;
+  buffers_.erase(it);
+}
+
 void BufferTracker::RemoveBuffer(GLuint client_id) {
   BufferMap::iterator it = buffers_.find(client_id);
   if (it != buffers_.end()) {
@@ -60,8 +67,19 @@ void BufferTracker::FreePendingToken(Buffer* buffer, int32 token) {
   buffer->shm_id_ = 0;
   buffer->shm_offset_ = 0;
   buffer->address_ = NULL;
+  buffer->unused_token_ = 0;
 }
 
+void BufferTracker::Free(Buffer* buffer) {
+  if (buffer->address_)
+    mapped_memory_->Free(buffer->address_);
+
+  buffer->size_ = 0;
+  buffer->shm_id_ = 0;
+  buffer->shm_offset_ = 0;
+  buffer->address_ = NULL;
+  buffer->unused_token_ = 0;
+}
 
 }  // namespace gles2
 }  // namespace gpu