Move cc/debug/latency_info to ui/base.

This structure would be useful in ui/surface, which can't depend on cc/.

BUG=

Review URL: https://chromiumcodereview.appspot.com/14999012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202772 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 139 insertions, 0 deletions

diff --git a/ui/base/OWNERS b/ui/base/OWNERS
new file mode 100644
index 0000000..5ff0082
--- /dev/null
+++ b/ui/base/OWNERS
@@ -0,0 +1 @@
+per-file latency_info.*=jbauman@chromium.org
diff --git a/ui/base/latency_info.cc b/ui/base/latency_info.cc
new file mode 100644
index 0000000..2d37585
--- /dev/null
+++ b/ui/base/latency_info.cc
@@ -0,0 +1,66 @@
+// 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 "ui/base/latency_info.h"
+
+#include <algorithm>
+
+namespace ui {
+
+LatencyInfo::LatencyInfo() {
+}
+
+LatencyInfo::~LatencyInfo() {
+}
+
+void LatencyInfo::MergeWith(const LatencyInfo& other) {
+  for (LatencyMap::const_iterator it = other.latency_components.begin();
+       it != other.latency_components.end();
+       ++it) {
+    AddLatencyNumberWithTimestamp(it->first.first,
+                                  it->first.second,
+                                  it->second.sequence_number,
+                                  it->second.event_time,
+                                  it->second.event_count);
+  }
+}
+
+void LatencyInfo::AddLatencyNumber(LatencyComponentType component,
+                                   int64 id,
+                                   int64 component_sequence_number) {
+  AddLatencyNumberWithTimestamp(component, id, component_sequence_number,
+                                base::TimeTicks::Now(), 1);
+}
+
+void LatencyInfo::AddLatencyNumberWithTimestamp(LatencyComponentType component,
+                                                int64 id,
+                                                int64 component_sequence_number,
+                                                base::TimeTicks time,
+                                                uint32 event_count) {
+  LatencyMap::key_type key = std::make_pair(component, id);
+  LatencyMap::iterator it = latency_components.find(key);
+  if (it == latency_components.end()) {
+    LatencyComponent info = {component_sequence_number, time, event_count};
+    latency_components[key] = info;
+    return;
+  }
+  it->second.sequence_number = std::max(component_sequence_number,
+                                        it->second.sequence_number);
+  uint32 new_count = event_count + it->second.event_count;
+  if (event_count > 0 && new_count != 0) {
+    // Do a weighted average, so that the new event_time is the average of
+    // the times of events currently in this structure with the time passed
+    // into this method.
+    it->second.event_time += (time - it->second.event_time) * event_count /
+        new_count;
+    it->second.event_count = new_count;
+  }
+}
+
+void LatencyInfo::Clear() {
+  latency_components.clear();
+}
+
+}  // namespace ui
+
diff --git a/ui/base/latency_info.h b/ui/base/latency_info.h
new file mode 100644
index 0000000..718fbb4
--- /dev/null
+++ b/ui/base/latency_info.h
@@ -0,0 +1,70 @@
+// 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.
+
+#ifndef UI_BASE_LATENCY_INFO_H_
+#define UI_BASE_LATENCY_INFO_H_
+
+#include <map>
+#include <utility>
+
+#include "base/basictypes.h"
+#include "base/time.h"
+#include "ui/base/ui_export.h"
+
+namespace ui {
+
+enum LatencyComponentType {
+  INPUT_EVENT_LATENCY_COMPONENT,
+};
+
+struct UI_EXPORT LatencyInfo {
+  struct LatencyComponent {
+    // Nondecreasing number that can be used to determine what events happened
+    // in the component at the time this struct was sent on to the next
+    // component.
+    int64 sequence_number;
+    // Average time of events that happened in this component.
+    base::TimeTicks event_time;
+    // Count of events that happened in this component
+    uint32 event_count;
+  };
+
+  // Map a Latency Component (with a component-specific int64 id) to a
+  // component info.
+  typedef std::map<std::pair<LatencyComponentType, int64>, LatencyComponent>
+      LatencyMap;
+
+  LatencyInfo();
+
+  ~LatencyInfo();
+
+  // Merges the contents of another LatencyInfo into this one.
+  void MergeWith(const LatencyInfo& other);
+
+  // Modifies the current sequence number for a component, and adds a new
+  // sequence number with the current timestamp.
+  void AddLatencyNumber(LatencyComponentType component,
+                        int64 id,
+                        int64 component_sequence_number);
+
+  // Modifies the current sequence number and adds a certain number of events
+  // for a specific component.
+  void AddLatencyNumberWithTimestamp(LatencyComponentType component,
+                                     int64 id,
+                                     int64 component_sequence_number,
+                                     base::TimeTicks time,
+                                     uint32 event_count);
+
+  void Clear();
+
+  LatencyMap latency_components;
+
+  // This represents the final time that a frame is displayed it.
+  base::TimeTicks swap_timestamp;
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_LATENCY_INFO_H_
+
diff --git a/ui/ui.gyp b/ui/ui.gyp
index 354efbe..71a3fdc 100644
--- a/ui/ui.gyp
+++ b/ui/ui.gyp
@@ -230,6 +230,8 @@
         'base/keycodes/keyboard_code_conversion_x.h',
         'base/keycodes/keyboard_codes.h',
         'base/keycodes/usb_keycode_map.h',
+        'base/latency_info.cc',
+        'base/latency_info.h',
         'base/l10n/l10n_font_util.cc',
         'base/l10n/l10n_font_util.h',
         'base/l10n/l10n_util.cc',