Trace some interesting events

Bug: 18337099
Change-Id: Ie2e60da2b9f06e0368061c944d8123ab6903355c
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 6c3637d..39528be 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -71,6 +71,8 @@
 }
 
 void CanvasContext::setSurface(ANativeWindow* window) {
+    ATRACE_CALL();
+
     mNativeWindow = window;
 
     if (mEglSurface != EGL_NO_SURFACE) {