Turn off verbose logging

This CL turns off the verbose logging if LOG_NDEBUG is 1, or if NDEBUG
is defined.  You can set the environment variable LOG_NDEBUG to 0 to
turn on verbose debugging for the CDM library on android.

Also, as in b/9672657, some applications call SelectKey when switching
between video and audio, which is much too verbose and affects
playback.  I have removed the log statements for SelectKey.

bug: 9672657

Change-Id: I635b997118996871356f7126852b4744fb05e810

libwvdrmengine/cdm/src/log.cpp

@@ -2,6 +2,20 @@
 //
 // Log - implemented using the standard Android logging mechanism
 
+/*
+ * Qutoing from system/core/include/log/log.h:
+ * Normally we strip ALOGV (VERBOSE messages) from release builds.
+ * You can modify this (for example with "#define LOG_NDEBUG 0"
+ * at the top of your source file) to change that behavior.
+ */
+#ifndef LOG_NDEBUG
+#ifdef NDEBUG
+#define LOG_NDEBUG 1
+#else
+#define LOG_NDEBUG 0
+#endif
+#endif
+
 #define LOG_TAG "WVCdm"
 #define LOG_BUF_SIZE 1024
 
@@ -26,7 +40,11 @@ void Log(const char* file, int line, LogPriority level, const char* fmt, ...) {
     case LOG_WARN: prio = ANDROID_LOG_WARN; break;
     case LOG_INFO: prio = ANDROID_LOG_INFO; break;
     case LOG_DEBUG: prio = ANDROID_LOG_DEBUG; break;
+#if LOG_NDEBUG
+    case LOG_VERBOSE: return;
+#else
     case LOG_VERBOSE: prio = ANDROID_LOG_VERBOSE; break;
+#endif
   }
 
   __android_log_write(prio, LOG_TAG, buf);