Switch LatencyInfo struct to use a map.

This allows us to have multiple instances of a specific component, for example each renderer will have a separate main thread and compositor.

BUG=155367

Review URL: https://codereview.chromium.org/13874002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194687 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 108 insertions, 10 deletions

diff --git a/cc/cc.gyp b/cc/cc.gyp
index b0ef550..692e555 100644
--- a/cc/cc.gyp
+++ b/cc/cc.gyp
@@ -98,6 +98,7 @@
       'layers/io_surface_layer_impl.h',
       'animation/keyframed_animation_curve.cc',
       'animation/keyframed_animation_curve.h',
+      'debug/latency_info.cc',
       'debug/latency_info.h',
       'layers/layer.cc',
       'layers/layer.h',
diff --git a/cc/debug/latency_info.cc b/cc/debug/latency_info.cc
new file mode 100644
index 0000000..0664dfb
--- /dev/null
+++ b/cc/debug/latency_info.cc
@@ -0,0 +1,61 @@
+// Copyright (c) 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 "cc/debug/latency_info.h"
+
+#include <algorithm>
+
+namespace cc {
+
+LatencyInfo::LatencyInfo() {
+}
+
+LatencyInfo::~LatencyInfo() {
+}
+
+void LatencyInfo::MergeWith(const LatencyInfo& other) {
+  for (LatencyMap::const_iterator b = other.latency_components.begin();
+      b != other.latency_components.end(); ++b) {
+    AddLatencyNumberWithTimestamp(b->first.first, b->first.second,
+                                  b->second.sequence_number,
+                                  b->second.event_time,
+                                  b->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 f = latency_components.find(key);
+  if (f == latency_components.end()) {
+    LatencyComponent info = {component_sequence_number, time, event_count};
+    latency_components[key] = info;
+  } else {
+    f->second.sequence_number = std::max(component_sequence_number,
+                                         f->second.sequence_number);
+    uint32 new_count = event_count + f->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.
+      f->second.event_time += (time - f->second.event_time) * event_count /
+          new_count;
+      f->second.event_count += new_count;
+    }
+  }
+}
+
+void LatencyInfo::Clear() {
+  latency_components.clear();
+}
+
+} // namespace cc
+
diff --git a/cc/debug/latency_info.h b/cc/debug/latency_info.h
index 1e75db8..e967caf 100644
--- a/cc/debug/latency_info.h
+++ b/cc/debug/latency_info.h
@@ -5,23 +5,59 @@
 #ifndef CC_DEBUG_LATENCY_INFO_H_
 #define CC_DEBUG_LATENCY_INFO_H_
 
+#include <map>
+#include <utility>
+
+#include "base/basictypes.h"
 #include "base/time.h"
+#include "cc/base/cc_export.h"
 
 namespace cc {
 
-struct LatencyInfo {
-  int64 renderer_main_frame_number;
-  int64 renderer_impl_frame_number;
-  int64 browser_main_frame_number;
-  int64 browser_impl_frame_number;
+enum LatencyComponentType {
+  kRendererMainThread,
+  kRendererImplThread,
+  kBrowserMainThread,
+  kBrowserImplThread,
+  kInputEvent,
+};
+
+struct CC_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;
+
+  LatencyMap latency_components;
 
+  // This represents the final time that a frame is displayed it.
   base::TimeTicks swap_timestamp;
 
-  LatencyInfo() :
-      renderer_main_frame_number(0),
-      renderer_impl_frame_number(0),
-      browser_main_frame_number(0),
-      browser_impl_frame_number(0) {}
+  LatencyInfo();
+
+  ~LatencyInfo();
+
+  void MergeWith(const LatencyInfo& other);
+
+  void AddLatencyNumber(LatencyComponentType component, int64 id,
+                        int64 component_sequence_number);
+  void AddLatencyNumberWithTimestamp(LatencyComponentType component,
+                                     int64 id, int64 component_sequence_number,
+                                     base::TimeTicks time,
+                                     uint32 event_count);
+
+  void Clear();
 };
 
 }  // namespace cc