Improve logging around performance critical events

bug:17702227

Add details useful to developers (such as layer size/View name), and
switch away from logging implementation names/details, since they
are generally not relevant to developers.

Change-Id: Iee605d182f241450f7e75a6d0c283d51fa1312f5
diff --git a/libs/hwui/RenderNode.cpp b/libs/hwui/RenderNode.cpp
index 13c5499..eb0948f 100644
--- a/libs/hwui/RenderNode.cpp
+++ b/libs/hwui/RenderNode.cpp
@@ -25,7 +25,6 @@
 #include <SkCanvas.h>
 #include <algorithm>
 
-#include <utils/Trace.h>
 
 #include "DamageAccumulator.h"
 #include "Debug.h"
@@ -34,6 +33,7 @@
 #include "LayerRenderer.h"
 #include "OpenGLRenderer.h"
 #include "utils/MathUtils.h"
+#include "utils/TraceUtils.h"
 #include "renderthread/CanvasContext.h"
 
 namespace android {
@@ -426,6 +426,10 @@
                 clipFlags = 0; // all clipping done by saveLayer
             }
 
+            ATRACE_FORMAT("%s alpha caused %ssaveLayer %ux%u",
+                    getName(), clipFlags ? "" : "unclipped ",
+                    layerBounds.getWidth(), layerBounds.getHeight());
+
             SaveLayerOp* op = new (handler.allocator()) SaveLayerOp(
                     layerBounds.left, layerBounds.top, layerBounds.right, layerBounds.bottom,
                     properties().getAlpha() * 255, saveFlags);