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

ui/events/latency_info.cc

 // 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 "base/debug/trace_event.h"
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/stringprintf.h"
 #include "ui/events/latency_info.h"
 
@@ skipping 217 matching lines @@
   latency_components.clear();
 }
 
 void LatencyInfo::TraceEventType(const char* event_type) {
   TRACE_EVENT_ASYNC_STEP_INTO0("benchmark",
                                "InputLatency",
                                TRACE_ID_DONT_MANGLE(trace_id),
                                event_type);
 }
 
+void LatencyInfo::AnnotateWithProcessId(
+    std::vector<ui::LatencyInfo>& latency_info,
+    base::ProcessId process_id) {
+  for (size_t i = 0; i < latency_info.size(); i++) {
+    latency_info[i].AnnotateComponentsWithProcessId(process_id);
+  }
+}
+
+void LatencyInfo::AnnotateComponentsWithProcessId(base::ProcessId process_id) {
+  LatencyMap::iterator lc = latency_components.begin();
+  while (lc != latency_components.end()) {
+    LatencyComponentType component_type = lc->first.first;
+    if (component_type == WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT) {
+      // If the component's process ID is kNullProcessId, patch it with the
+      // correct value.
+      int component_process_id = (lc->first.second >> 32) & 0xffffffff;
+      if (component_process_id == base::kNullProcessId) {
+        // Generate a new component entry
+        int routing_id = lc->first.second & 0xffffffff;
+        int64 id = routing_id | (static_cast<int64>(process_id) << 32);
+        LatencyMap::key_type key = std::make_pair(component_type, id);
+        latency_components[key] = lc->second;
+
+        // Remove the old entry
+        LatencyMap::iterator eraseIter = lc;
+        ++lc;
+        latency_components.erase(eraseIter);
+
+        continue;
+      }
+    }
+
+    ++lc;
+  }
+}
+
 }  // namespace ui