Merge pull request #2239 from abarth/trace_compositor

Add some more trace events to the compositor

sky/compositor/layer_tree.cc

@@ -4,6 +4,7 @@
 
 #include "sky/compositor/layer_tree.h"
 
+#include "base/trace_event/trace_event.h"
 #include "sky/compositor/layer.h"
 
 namespace sky {
@@ -16,9 +17,16 @@ LayerTree::~LayerTree() {
 }
 
 void LayerTree::Raster(PaintContext::ScopedFrame& frame) {
-  Layer::PrerollContext context = { frame, SkRect::MakeEmpty() };
-  root_layer_->Preroll(&context, SkMatrix());
-  root_layer_->Paint(frame);
+  {
+    TRACE_EVENT0("flutter", "LayerTree::Preroll")
+    Layer::PrerollContext context = { frame, SkRect::MakeEmpty() };
+    root_layer_->Preroll(&context, SkMatrix());
+  }
+
+  {
+    TRACE_EVENT0("flutter", "LayerTree::Paint")
+    root_layer_->Paint(frame);
+  }
 }
 
 }  // namespace compositor

sky/compositor/raster_cache.cc

@@ -4,8 +4,9 @@
 
 #include "sky/compositor/raster_cache.h"
 
-#include "sky/compositor/paint_context.h"
 #include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+#include "sky/compositor/paint_context.h"
 #include "third_party/skia/include/core/SkImage.h"
 
 #define ENABLE_RASTER_CACHE 0
@@ -73,6 +74,9 @@ RefPtr<SkImage> RasterCache::GetPrerolledImage(GrContext* context,
     entry.access_count = kRasterThreshold;
 
     if (!entry.image && isWorthRasterizing(picture)) {
+      TRACE_EVENT2("flutter", "Rasterize picture layer",
+                   "width", physical_size.width(),
+                   "height", physical_size.height());
       SkMatrix matrix = SkMatrix::MakeScale(scaleX, scaleY);
       entry.image = adoptRef(SkImage::NewFromPicture(picture, physical_size,
                                                      &matrix, nullptr));

sky/engine/core/script/dart_init.cc

@@ -72,6 +72,9 @@ static const char* kDartArgs[] = {
     // default profile period to 100Hz. This number is suitable for older
     // Raspberry Pi devices but quite low for current smartphones.
     "--profile_period=1000",
+    // Background compilation isn't quite ready, but this flag turns it on if we
+    // want to experiment with it.
+    // "--background_compilation",
 #if (WTF_OS_IOS || WTF_OS_MACOSX)
     // On platforms where LLDB is the primary debugger, SIGPROF signals
     // overwhelm LLDB.