Deprecates HttpThrowableReporter in favor of JsonLogRecordClientUtil.

This helps us to drop XMLHttpRequest dep from core which makes it
easier to avoid circular deps involving core.

Change-Id: I21ef3393310c19112aeb904f4b970bc89ebbacaa
(cherry picked from commit d94b402596302381061b72698bc706257307a4e7)

user/src/com/google/gwt/core/client/HttpThrowableReporter.java

diff --git a/user/src/com/google/gwt/core/client/HttpThrowableReporter.java b/user/src/com/google/gwt/core/client/HttpThrowableReporter.java
index 5088667..603f678 100644
--- a/user/src/com/google/gwt/core/client/HttpThrowableReporter.java
+++ b/user/src/com/google/gwt/core/client/HttpThrowableReporter.java
@@ -21,7 +21,10 @@
 /**
  * This is a utility class which can report Throwables to the server via a
  * JSON-formatted payload.
+ *
+ * @deprecated Use {@link JsonLogRecordClientUtil} instead.
  */
+@Deprecated
 public final class HttpThrowableReporter {
 
   private static class MyHandler implements UncaughtExceptionHandler {

user/src/com/google/gwt/logging/client/JsonLogRecordClientUtil.java

diff --git a/user/src/com/google/gwt/logging/client/JsonLogRecordClientUtil.java b/user/src/com/google/gwt/logging/client/JsonLogRecordClientUtil.java
index 1c9b153..b2224a6 100644
--- a/user/src/com/google/gwt/logging/client/JsonLogRecordClientUtil.java
+++ b/user/src/com/google/gwt/logging/client/JsonLogRecordClientUtil.java
@@ -32,6 +32,10 @@
  */
 public class JsonLogRecordClientUtil {
 
+  public static String throwableAsJson(Throwable t) {
+    return throwableAsJsonObject(t).toString();
+  }
+
   public static String logRecordAsJson(LogRecord lr) {
     return logRecordAsJsonObject(lr).toString();
   }