Removed requirement for the renderer to know it's process ID

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 06aa4dd1a62230a234903d7d2d8f8b2aa1b2a322..45d8aaf2c466e0dc0fe100b91564e8157e64a033 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -1498,6 +1498,7 @@ void RenderWidgetHostImpl::OnCompositorSurfaceBuffersSwapped(
   gpu_params.size = params.size;
   gpu_params.scale_factor = params.scale_factor;
   gpu_params.latency_info = params.latency_info;
+  FixMissingLatencyInfoComponentIds(gpu_params.latency_info);
   view_->AcceleratedSurfaceBuffersSwapped(gpu_params,
                                           params.gpu_process_host_id);
   view_->DidReceiveRendererFrame();
@@ -1513,6 +1514,9 @@ bool RenderWidgetHostImpl::OnSwapCompositorFrame(
   uint32 output_surface_id = param.a;
   param.b.AssignTo(frame.get());
 
+  for (size_t i = 0; i < frame->metadata.latency_info.size(); i++)
+    FixMissingLatencyInfoComponentIds(frame->metadata.latency_info[i]);
+
   input_router_->OnViewUpdated(
       GetInputRouterViewFlagsFromCompositorFrameMetadata(frame->metadata));
 
@@ -1677,9 +1681,17 @@ void RenderWidgetHostImpl::DidUpdateBackingStore(
 
   // Now paint the view. Watch out: it might be destroyed already.
   if (view_ && !is_accelerated_compositing_active_) {
+
+    std::vector<ui::LatencyInfo> latency_info;
+    for (size_t i = 0; i < params.latency_info.size(); i++) {
+      ui::LatencyInfo info = params.latency_info[i];
+      FixMissingLatencyInfoComponentIds(info);
+      latency_info.push_back(info);
+    }
+
     view_being_painted_ = true;
     view_->DidUpdateBackingStore(params.scroll_rect, params.scroll_delta,
-                                 params.copy_rects, params.latency_info);
+                                 params.copy_rects, latency_info);
     view_->DidReceiveRendererFrame();
     view_being_painted_ = false;
   }
@@ -2512,4 +2524,27 @@ void RenderWidgetHostImpl::CompositorFrameDrawn(
   }
 }
 
+void RenderWidgetHostImpl::FixMissingLatencyInfoComponentIds(
+    ui::LatencyInfo& latency_info) {
+  ui::LatencyInfo::LatencyMap::iterator lc =
+      latency_info.latency_components.begin();
+  while (lc != latency_info.latency_components.end()) {
+    ui::LatencyComponentType component_type = lc->first.first;
+    if (component_type == ui::WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT) {
+      // If the component's ID is 0, patch it with the correct value.
+      if (lc->first.second == 0) {

[jam, 2014/01/17 01:27:27]

i think we should always set it if it's coming from the renderer. that way a
renderer can't put a non-zero value and then we'd trust it.

+        // Generate a new component entry
+        ui::LatencyInfo::LatencyMap::key_type key =
+            std::make_pair(component_type, GetLatencyComponentId());
+        latency_info.latency_components[key] = lc->second;
+
+        // Remove the old entry
+        latency_info.latency_components.erase(lc++);
+        continue;
+      }
+    }
+    ++lc;
+  }
+}
+
 }  // namespace content