sync compositor: Add output_surface_id

android_webview/browser/shared_renderer_state.cc

Index: android_webview/browser/shared_renderer_state.cc
diff --git a/android_webview/browser/shared_renderer_state.cc b/android_webview/browser/shared_renderer_state.cc
index e81ab1261ec7d19e7a71cfb406070b3a7afa314d..9fd1a48ab70b0d118e818661b20d6392bce2e900 100644
--- a/android_webview/browser/shared_renderer_state.cc
+++ b/android_webview/browser/shared_renderer_state.cc
@@ -213,18 +213,32 @@ bool SharedRendererState::IsInsideHardwareRelease() const {
   return inside_hardware_release_;
 }
 
+SharedRendererState::ReturnedResources::ReturnedResources()
+    : output_surface_id(0u) {}
+
+SharedRendererState::ReturnedResources::~ReturnedResources() {}
+
 void SharedRendererState::InsertReturnedResourcesOnRT(
     const cc::ReturnedResourceArray& resources,
-    uint32_t compositor_id) {
+    uint32_t compositor_id,
+    uint32_t output_surface_id) {
   base::AutoLock lock(lock_);
-  cc::ReturnedResourceArray& returned_resources =
+  ReturnedResources& returned_resources =
       returned_resources_map_[compositor_id];
-  returned_resources.insert(returned_resources.end(), resources.begin(),
-                            resources.end());
+  if (returned_resources.output_surface_id != output_surface_id) {
+    if ((returned_resources.output_surface_id - output_surface_id) <

[hush (inactive), 2016/03/15 00:05:59]

i guess you can also do:
if (output_surface_id - returned_sources.output_surface_id > 0x80000000)

But anyway, a comment here would be great. The effort to address wrapping case
is also just best effort, I think.

+        0x80000000) {
+      return;
+    }
+    returned_resources.resources.clear();
+  }
+  returned_resources.resources.insert(returned_resources.resources.end(),
+                                      resources.begin(), resources.end());
+  returned_resources.output_surface_id = output_surface_id;
 }
 
 void SharedRendererState::SwapReturnedResourcesOnUI(
-    std::map<uint32_t, cc::ReturnedResourceArray>* returned_resource_map) {
+    ReturnedResourcesMap* returned_resource_map) {
   DCHECK(returned_resource_map->empty());
   base::AutoLock lock(lock_);
   returned_resource_map->swap(returned_resources_map_);