Additional layer logging, and added mutex

bug:17208461
Change-Id: I006d432a3b633235dde0b81ad2bf28b835b5335f
diff --git a/libs/hwui/RenderState.h b/libs/hwui/RenderState.h
index c7ab197..74bafca 100644
--- a/libs/hwui/RenderState.h
+++ b/libs/hwui/RenderState.h
@@ -19,6 +19,7 @@
 #include <set>
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
+#include <utils/Mutex.h>
 
 #include <private/hwui/DrawGlInfo.h>
 
@@ -52,9 +53,11 @@
     void debugOverdraw(bool enable, bool clear);
 
     void registerLayer(const Layer* layer) {
+        AutoMutex _lock(mLayerLock);
         mActiveLayers.insert(layer);
     }
     void unregisterLayer(const Layer* layer) {
+        AutoMutex _lock(mLayerLock);
         mActiveLayers.erase(layer);
     }
 
@@ -83,6 +86,7 @@
     GLsizei mViewportWidth;
     GLsizei mViewportHeight;
     GLuint mFramebuffer;
+    Mutex mLayerLock;
 };
 
 } /* namespace uirenderer */