wm: Avoid log spew in window manager logs.

On developer builds (where NDEBUG is not defined), the window
manager logs are growing uncontrollably.  After a few days (Nov 17
though Nov 21), I've got almost a gigabyte of logs:

  # du -sh /var/log/window_manager/
  923M /var/log/window_manager/

This machine has really just been sitting at the login prompt.
After the initial bit of debug info, logs are filled with:

  [1121/131449:21180773:INFO:opengles_visitor.cc(227)] Performing partial screen update: 405, 570, 23, 22.
  [1121/131449:21181179:INFO:opengles_visitor.cc(267)] Visit container: stage
  [1121/131449:21258991:INFO:opengles_visitor.cc(227)] Performing partial screen update: 405, 570, 23, 22.
  [1121/131449:21259441:INFO:opengles_visitor.cc(267)] Visit container: stage
  [1121/131449:21336403:INFO:opengles_visitor.cc(227)] Performing partial screen update: 405, 570, 23, 22.
  [1121/131449:21336905:INFO:opengles_visitor.cc(267)] Visit container: stage

These messages aren't providing enough useful information to the
average user to justify such log spew.  Deleting them so that we can
still keep other INFO-level logs around but don't get these ones.

NOTE that filling up /var/log so badly had the effect of
making all autotests take forever, so this should really help the
average developer.

BUG=None
TEST=Emerged and saw that log spew was gone.

Change-Id: I60d727bb8f37456a232d75aed8eabc5c59fdf0e0
Reviewed-on: https://gerrit.chromium.org/gerrit/12011
Tested-by: Doug Anderson <[email protected]>
Reviewed-by: Stéphane Marchesin <[email protected]>
Commit-Ready: Doug Anderson <[email protected]>
Reviewed-by: Daniel Erat <[email protected]>
diff --git a/compositor/gles/opengles_visitor.cc b/compositor/gles/opengles_visitor.cc
index 1a27b86..437cb33 100644
--- a/compositor/gles/opengles_visitor.cc
+++ b/compositor/gles/opengles_visitor.cc
@@ -21,6 +21,9 @@
 #error Need COMPOSITOR_OPENGLES defined to compile this file
 #endif
 
+// Turn this on if you want to debug something in this file in depth.
+#undef EXTRA_LOGGING
+
 namespace window_manager {
 
 OpenGlesDrawVisitor::OpenGlesDrawVisitor(Gles2Interface* gl,
@@ -223,6 +226,7 @@
     }
   }
 
+#ifdef EXTRA_LOGGING
   if (do_partial_update) {
     DLOG(INFO) << "Performing partial screen update: "
                << damaged_region_.x << ", "
@@ -232,6 +236,7 @@
   } else {
     DLOG(INFO) << "Performing fullscreen update.";
   }
+#endif
 
   // No need to clear color buffer if something will cover up the screen.
   if (!has_fullscreen_actor_)
@@ -264,7 +269,9 @@
   if (!actor->IsVisible())
     return;
 
+#ifdef EXTRA_LOGGING
   LOG(INFO) << "Visit container: " << actor->name();
+#endif
 
   const float original_opacity = ancestor_opacity_;
   ancestor_opacity_ *= actor->opacity();