Aura/ÜC: Drop frames on background tabs

content/browser/renderer_host/renderer_frame_manager.cc

Index: content/browser/renderer_host/renderer_frame_manager.cc
diff --git a/content/browser/renderer_host/renderer_frame_manager.cc b/content/browser/renderer_host/renderer_frame_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3d16361828d3707af4ba58bc1d3c69b709653e50
--- /dev/null
+++ b/content/browser/renderer_host/renderer_frame_manager.cc
@@ -0,0 +1,60 @@
+// Copyright 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/browser/renderer_host/renderer_frame_manager.h"
+
+#include "base/logging.h"
+#include "base/sys_info.h"
+
+namespace content {
+
+RendererFrameManager* RendererFrameManager::GetInstance() {
+  return Singleton<RendererFrameManager>::get();
+}
+
+void RendererFrameManager::AddFrame(RendererFrameManagerClient* frame,
+                                    bool visible) {
+  RemoveFrame(frame);
+  if (visible)
+    visible_frames_.insert(frame);
+  else
+    hidden_frames_.push_front(frame);
+  CullHiddenFrames();
+}
+
+void RendererFrameManager::RemoveFrame(RendererFrameManagerClient* frame) {
+  visible_frames_.erase(frame);
+  hidden_frames_.remove(frame);
+}
+
+void RendererFrameManager::SetFrameVisibility(RendererFrameManagerClient* frame,
+                                              bool visible) {
+  if (visible) {
+    hidden_frames_.remove(frame);
+    visible_frames_.insert(frame);
+  } else {
+    visible_frames_.erase(frame);
+    hidden_frames_.push_front(frame);
+    CullHiddenFrames();
+  }
+}
+
+RendererFrameManager::RendererFrameManager()
+    : max_number_of_saved_frames_(
+          std::min(5, 2 + (base::SysInfo::AmountOfPhysicalMemoryMB() / 256))) {}
+
+RendererFrameManager::~RendererFrameManager() {}
+
+void RendererFrameManager::CullHiddenFrames() {
+  while (!hidden_frames_.empty() &&
+         hidden_frames_.size() + visible_frames_.size() >
+             max_number_of_saved_frames()) {
+    size_t old_size = hidden_frames_.size();
+    // Should remove self from list.
+    hidden_frames_.back()->EvictCurrentFrame();
+    DCHECK_EQ(hidden_frames_.size() + 1, old_size);
+  }
+}
+
+}  // namespace content