Remove gpu side LatencyInfo merging

content/browser/renderer_host/render_process_host_impl.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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 144 matching lines @@
 
 #include "third_party/skia/include/core/SkBitmap.h"
 
 extern bool g_exited_main_message_loop;
 
 static const char* kSiteProcessMapKeyName = "content_site_process_map";
 
 namespace content {
 namespace {
 
+// Maximal number of LatencyInfo that can be contained in
+// ViewHostMsg_CompositorSurfaceBuffersSwapped_Params.
+const unsigned int kMaxLatencyInfoNumber = 100;
+
 void CacheShaderInfo(int32 id, base::FilePath path) {
   ShaderCacheFactory::GetInstance()->SetCacheInfo(id, path);
 }
 
 void RemoveShaderInfo(int32 id) {
   ShaderCacheFactory::GetInstance()->RemoveCacheInfo(id);
 }
 
 net::URLRequestContext* GetRequestContext(
     scoped_refptr<net::URLRequestContextGetter> request_context,
@@ skipping 1805 matching lines @@
 }
 
 void RenderProcessHostImpl::OnSavedPageAsMHTML(int job_id, int64 data_size) {
   MHTMLGenerationManager::GetInstance()->MHTMLGenerated(job_id, data_size);
 }
 
 void RenderProcessHostImpl::OnCompositorSurfaceBuffersSwappedNoHost(
       const ViewHostMsg_CompositorSurfaceBuffersSwapped_Params& params) {
   TRACE_EVENT0("renderer_host",
                "RenderWidgetHostImpl::OnCompositorSurfaceBuffersSwappedNoHost");
+  CHECK(params.latency_info.size() < kMaxLatencyInfoNumber);

[jln (very slow on Chromium), 2014/01/14 00:32:51]

The problem with this approach is that is gives a trivial denial of service from
a compromised renderer to the browser.

It's not a huge issue, but we would rather avoid that. Could we log an error and
ignore the message instead?

[Yufeng Shen (Slow to review), 2014/01/14 00:47:14]

Done.

   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
   ack_params.sync_point = 0;
   RenderWidgetHostImpl::AcknowledgeBufferPresent(params.route_id,
                                                  params.gpu_process_host_id,
                                                  ack_params);
 }
 
 void RenderProcessHostImpl::OnGpuSwitching() {
   // We are updating all widgets including swapped out ones.
   scoped_ptr<RenderWidgetHostIterator> widgets(
@@ skipping 18 matching lines @@
     return;
   Send(new MediaStreamMsg_EnableAecDump(file_for_transit));
 }
 
 void RenderProcessHostImpl::SendDisableAecDumpToRenderer() {
   Send(new MediaStreamMsg_DisableAecDump());
 }
 #endif
 
 }  // namespace content