Add fine-grained debug layer

Full GLES error checking layer via -include
trickery. Change DEBUG_OPENGL to a level system.

HIGH = every GL call is error checked
MODERATE = checkpointing at interesting spots
LOW = only asserts there are no errors at the end of a frame
 or when the FBO changes
NONE = AIN'T GOT NO TIME FOR ERRORS GOTTA GO FAST!

Change-Id: Ibe81aae93d942059c4ddf1cbb11c828b7ce4c10b
diff --git a/libs/hwui/Debug.h b/libs/hwui/Debug.h
index e98fa04..748edef 100644
--- a/libs/hwui/Debug.h
+++ b/libs/hwui/Debug.h
@@ -17,8 +17,18 @@
 #ifndef ANDROID_HWUI_DEBUG_H
 #define ANDROID_HWUI_DEBUG_H
 
+#define DEBUG_LEVEL_HIGH 3
+#define DEBUG_LEVEL_MODERATE 2
+#define DEBUG_LEVEL_LOW 1
+#define DEBUG_LEVEL_NONE 0
+
 // Turn on to check for OpenGL errors on each frame
-#define DEBUG_OPENGL 1
+// Note DEBUG_LEVEL_HIGH for DEBUG_OPENGL is only setable by enabling
+// HWUI_ENABLE_OPENGL_VALIDATION when building HWUI. Similarly if
+// HWUI_ENABLE_OPENGL_VALIDATION is set then this is always DEBUG_LEVEL_HIGH
+#ifndef DEBUG_OPENGL
+#define DEBUG_OPENGL DEBUG_LEVEL_LOW
+#endif
 
 // Turn on to enable initialization information
 #define DEBUG_INIT 0