[chromedriver] Prevent GetLog from returning more than 100,000 at a time.

chrome/test/chromedriver/logging_unittest.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/values.h"
 #include "chrome/test/chromedriver/capabilities.h"
 #include "chrome/test/chromedriver/chrome/devtools_event_listener.h"
@@ skipping 150 matching lines @@
   ASSERT_TRUE(entry.empty());
 
   log.AddEntry(Log::kInfo, "info message");
   log.AddEntry(Log::kError, "first error message");
   log.AddEntry(Log::kDebug, "debug message");
   log.AddEntry(Log::kError, "second error message");
 
   entry = log.GetFirstErrorMessage();
   ASSERT_EQ("first error message", entry);
 }
+
+TEST(Logging, GetLotsOfLogs) {
+  WebDriverLog log(WebDriverLog::kBrowserType, Log::kAll);
+  std::string entry;
+  for (size_t i = 0; i < WebDriverLog::kMaxReturnedEntries + 1; i++)
+    log.AddEntry(Log::kError, "info message");
+  std::unique_ptr<base::ListValue> entries = log.GetAndClearEntries();
+  ASSERT_EQ(WebDriverLog::kMaxReturnedEntries, entries->GetSize());
+  entries = log.GetAndClearEntries();
+  ASSERT_EQ(1u, entries->GetSize());
+  entries = log.GetAndClearEntries();
+  ASSERT_EQ(0u, entries->GetSize());
+}