Implement query translation from GData WAPI to Drive API v2.

chrome/browser/google_apis/drive_api_util.h

Index: chrome/browser/google_apis/drive_api_util.h
diff --git a/chrome/browser/google_apis/drive_api_util.h b/chrome/browser/google_apis/drive_api_util.h
index 2ff8b33ca9d91cf994331ca686c2ecd7c4432f0c..4206106ba2d9140e7ef36d900f33f55ac3f5a414 100644
--- a/chrome/browser/google_apis/drive_api_util.h
+++ b/chrome/browser/google_apis/drive_api_util.h
@@ -23,6 +23,16 @@ namespace util {
 // See also: https://developers.google.com/drive/search-parameters
 std::string EscapeQueryStringValue(const std::string& str);
 
+// Parses the query, and builds a search query for Drive API v2.
+// This only supports:
+//   Regular query (e.g. dog => fullText contains 'dog')
+//   Conjunctions
+//     (e.g. dog cat => fullText contains 'dog' and fullText contains 'cat')
+//   Exclusion query (e.g. -cat => not fullText contains 'cat').
+//   Quoted query (e.g. "dog cat" => fullText contains 'dog cat').
+// See also: https://developers.google.com/drive/search-parameters
+std::string TranslateQuery(const std::string& original_query);
+
 }  // namespace util
 }  // namespace drive
 }  // namespace google_apis