Disable Drive API v2 for M-28 release.

chrome/browser/google_apis/drive_api_util.cc

 // Copyright (c) 2012 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 "chrome/browser/google_apis/drive_api_util.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/string16.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/google_apis/drive_switches.h"
 
 namespace google_apis {
 namespace util {
 
 bool IsDriveV2ApiEnabled() {
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
+
+  // Disable Drive API v2 by default.
+  if (!command_line->HasSwitch(switches::kEnableDriveV2Api))
+    return false;
+
   std::string value =
       command_line->GetSwitchValueASCII(switches::kEnableDriveV2Api);
   StringToLowerASCII(&value);
-  if (value == "false") {
-    return false;
-  }
-
-  // The value should be empty or "true".
-  DCHECK(value.empty() || value == "true");
-  return true;
+  // The value must be "" or "true" for true, or "false" for false.
+  DCHECK(value.empty() || value == "true" || value == "false");
+  return value != "false";
 }
 
 }  // namespace util
 
 namespace drive {
 namespace util {
 
 std::string EscapeQueryStringValue(const std::string& str) {
   std::string result;
   result.reserve(str.size());
@@ skipping 68 matching lines @@
         is_exclusion ? "not " : "",
         EscapeQueryStringValue(UTF16ToUTF8(token)).c_str());
   }
 
   return result;
 }
 
 }  // namespace util
 }  // namespace drive
 }  // namespace google_apis