NOT READY FOR REVIEW - switch to a subscriber model for rendering stats

cc/layer_tree_host_impl.cc

 // Copyright 2011 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 "config.h"
 
 #include "cc/layer_tree_host_impl.h"
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
 #include "cc/append_quads_data.h"
 #include "cc/damage_tracker.h"
 #include "cc/debug_rect_history.h"
 #include "cc/delay_based_time_source.h"
 #include "cc/font_atlas.h"
 #include "cc/frame_rate_counter.h"
 #include "cc/gl_renderer.h"
 #include "cc/heads_up_display_layer_impl.h"
 #include "cc/layer_iterator.h"
 #include "cc/layer_tree_host.h"
 #include "cc/layer_tree_host_common.h"
 #include "cc/math_util.h"
 #include "cc/overdraw_metrics.h"
 #include "cc/page_scale_animation.h"
 #include "cc/prioritized_texture_manager.h"
 #include "cc/render_pass_draw_quad.h"
 #include "cc/rendering_stats.h"
+#include "cc/rendering_stats_subscriber.h"
 #include "cc/scrollbar_animation_controller.h"
 #include "cc/scrollbar_layer_impl.h"
 #include "cc/settings.h"
 #include "cc/single_thread_proxy.h"
 #include "cc/software_renderer.h"
 #include "cc/texture_uploader.h"
 #include <algorithm>
 
 using WebKit::WebTransformationMatrix;
 
@@ skipping 631 matching lines @@
 
 void LayerTreeHostImpl::drawLayers(const FrameData& frame)
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::drawLayers");
     DCHECK(canDraw());
     DCHECK(!frame.renderPasses.empty());
 
     // FIXME: use the frame begin time from the overall compositor scheduler.
     // This value is currently inaccessible because it is up in Chromium's
     // RenderWidget.
-    m_fpsCounter->markBeginningOfFrame(base::TimeTicks::Now());
+    base::TimeTicks now = base::TimeTicks::Now();
+    m_fpsCounter->markBeginningOfFrame(now);
+    if (m_renderingStatsSubscriber)
+        m_renderingStatsSubscriber->markBeginningOfFrame(now);
 
     if (m_settings.showDebugRects())
         m_debugRectHistory->saveDebugRectsForCurrentFrame(m_rootLayerImpl.get(), *frame.renderSurfaceLayerList, frame.occludingScreenSpaceRects, settings());
 
     // Because the contents of the HUD depend on everything else in the frame, the contents
     // of its texture are updated as the last thing before the frame is drawn.
     if (m_hudLayerImpl)
         m_hudLayerImpl->updateHudTexture(m_resourceProvider.get());
 
     m_renderer->drawFrame(frame.renderPasses, frame.renderPassesById);
@@ skipping 775 matching lines @@
 }
 
 void LayerTreeHostImpl::renderingStats(RenderingStats* stats) const
 {
     stats->numFramesSentToScreen = fpsCounter()->currentFrameNumber();
     stats->droppedFrameCount = fpsCounter()->droppedFrameCount();
     stats->numImplThreadScrolls = m_numImplThreadScrolls;
     stats->numMainThreadScrolls = m_numMainThreadScrolls;
 }
 
+void LayerTreeHostImpl::startRecordingRenderingStats()
+{
+    m_renderingStatsSubscriber = RenderingStatsSubscriber::create();
+}
+
+void LayerTreeHostImpl::stopRecordingRenderingStats(RenderingStats* stats)
+{
+    double frame_rate_average = 0.0;
+    double frame_rate_standard_deviation = 0.0;
+
+    m_renderingStatsSubscriber->getFPSAndStandardDeviation(
+        frame_rate_average,
+        frame_rate_standard_deviation);
+
+    stats->frameRateAverage = frame_rate_average;
+    stats->frameRateStandardDeviation = frame_rate_standard_deviation;
+
+    m_renderingStatsSubscriber.reset();
+}
+
 void LayerTreeHostImpl::animateScrollbars(base::TimeTicks time)
 {
     animateScrollbarsRecursive(m_rootLayerImpl.get(), time);
 }
 
 void LayerTreeHostImpl::animateScrollbarsRecursive(LayerImpl* layer, base::TimeTicks time)
 {
     if (!layer)
         return;
 
     ScrollbarAnimationController* scrollbarController = layer->scrollbarAnimationController();
     double monotonicTime = (time - base::TimeTicks()).InSecondsF();
     if (scrollbarController && scrollbarController->animate(monotonicTime))
         m_client->setNeedsRedrawOnImplThread();
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         animateScrollbarsRecursive(layer->children()[i], time);
 }
 
 }  // namespace cc