Log to webrtc logging stream from java code.

talk/app/webrtc/java/src/org/webrtc/Logging.java

Index: talk/app/webrtc/java/src/org/webrtc/Logging.java
diff --git a/talk/app/webrtc/java/src/org/webrtc/Logging.java b/talk/app/webrtc/java/src/org/webrtc/Logging.java
index 75f758978333561b16117413a993457992f4974e..58da68b7c1a3fa9fb2e206cbaaa0f8f25c80a130 100644
--- a/talk/app/webrtc/java/src/org/webrtc/Logging.java
+++ b/talk/app/webrtc/java/src/org/webrtc/Logging.java
@@ -27,6 +27,9 @@
 
 package org.webrtc;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.nio.charset.Charset;
 import java.util.EnumSet;
 
 /** Java wrapper for WebRTC & libjingle logging. */
@@ -84,12 +87,47 @@ public class Logging {
   }
 
   public static void log(Severity severity, String tag, String message) {
-    nativeLog(severity.ordinal(), tag + ": " + message);
+    nativeLog(severity.ordinal(), tag, message);
+  }
+
+  public static void d(String tag, String message) {
+    log(Severity.LS_INFO, tag, message);
+  }
+
+  public static void e(String tag, String message) {
+    log(Severity.LS_ERROR, tag, message);
+  }
+
+  public static void w(String tag, String message) {
+    log(Severity.LS_WARNING, tag, message);
+  }
+
+  public static void e(String tag, String message, Throwable e) {
+    log(Severity.LS_ERROR, tag, message);
+    log(Severity.LS_ERROR, tag, e.toString());
+    log(Severity.LS_ERROR, tag, getStackTraceAsString(e));
+  }
+
+  public static void w(String tag, String message, Throwable e) {
+    log(Severity.LS_WARNING, tag, message);
+    log(Severity.LS_WARNING, tag, e.toString());
+    log(Severity.LS_WARNING, tag, getStackTraceAsString(e));
+  }
+
+  public static void v(String tag, String message) {
+    log(Severity.LS_VERBOSE, tag, message);
+  }
+
+  private static String getStackTraceAsString(Throwable e) {

[AlexG, 2015/09/14 20:12:33]

May be mimic Android implementation here (getStackTraceString() from 
https://android.googlesource.com/platform/frameworks/base/+/534a67c/core/java...
)?

[jiayl2, 2015/09/14 20:54:38]

Done.

+    ByteArrayOutputStream ostream = new ByteArrayOutputStream();
+    PrintStream pstream = new PrintStream(ostream);
+    e.printStackTrace(pstream);
+    return ostream.toString();
   }
 
   private static native void nativeEnableTracing(
       String path, int nativeLevels, int nativeSeverity);
   private static native void nativeEnableLogThreads();
   private static native void nativeEnableLogTimeStamps();
-  private static native void nativeLog(int severity, String message);
+  private static native void nativeLog(int severity, String tag, String message);
 }