Make the rebaseline log server resilient to large logs.

Tools/RebaselineLogServer/main_unittest.py

Index: Tools/RebaselineLogServer/main_unittest.py
diff --git a/Tools/RebaselineLogServer/main_unittest.py b/Tools/RebaselineLogServer/main_unittest.py
index d3d6e30902a7109cb5195fdc517583853c2665a2..8477b20e236328a53b585cbecd40677a1066db16 100644
--- a/Tools/RebaselineLogServer/main_unittest.py
+++ b/Tools/RebaselineLogServer/main_unittest.py
@@ -73,6 +73,16 @@ class TestHandlers(unittest.TestCase):
 
         request = webapp2.Request.blank('/updatelog')
         request.method = 'POST'
+        request.POST[main.LOG_PARAM] = 'x' * 1000000
+        request.POST[main.NEW_ENTRY_PARAM] = 'off'
+        request.POST[main.NO_NEEDS_REBASELINE_PARAM] = 'off'
+
+        response = request.get_response(main.app)
+        self.assertEqual(response.status_int, 200)
+        self.assertEqual(response.body, 'Created new log entry because the previous one exceeded the max length.')
+
+        request = webapp2.Request.blank('/updatelog')
+        request.method = 'POST'
         request.POST[main.LOG_PARAM] = 'data to log'
         request.POST[main.NEW_ENTRY_PARAM] = 'off'
         request.POST[main.NO_NEEDS_REBASELINE_PARAM] = 'on'