Let JsonDoubleQuote accept StringPiece

So that the functions can escape 'const char*' or 'const char16*'
without creating a std::string or string16 object for the parameter.

BUG=none
TEST=StringEscapeTest.JsonDoubleQuoteNarrow

Review URL: https://chromiumcodereview.appspot.com/18648003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221625 0039d316-1c4b-4281-b951-d872f2087c98

base/json/string_escape.cc

@@ -78,25 +78,25 @@ void JsonDoubleQuoteT(const STR& str,
 
 }  // namespace
 
-void JsonDoubleQuote(const std::string& str,
+void JsonDoubleQuote(const StringPiece& str,
                      bool put_in_quotes,
                      std::string* dst) {
   JsonDoubleQuoteT(str, put_in_quotes, dst);
 }
 
-std::string GetDoubleQuotedJson(const std::string& str) {
+std::string GetDoubleQuotedJson(const StringPiece& str) {
   std::string dst;
   JsonDoubleQuote(str, true, &dst);
   return dst;
 }
 
-void JsonDoubleQuote(const string16& str,
+void JsonDoubleQuote(const StringPiece16& str,
                      bool put_in_quotes,
                      std::string* dst) {
   JsonDoubleQuoteT(str, put_in_quotes, dst);
 }
 
-std::string GetDoubleQuotedJson(const string16& str) {
+std::string GetDoubleQuotedJson(const StringPiece16& str) {
   std::string dst;
   JsonDoubleQuote(str, true, &dst);
   return dst;

base/json/string_escape.h

@@ -10,7 +10,7 @@
 #include <string>
 
 #include "base/base_export.h"
-#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
 
 namespace base {
 
@@ -19,19 +19,19 @@ namespace base {
 // If |put_in_quotes| is true, the result will be surrounded in double quotes.
 // The outputted literal, when interpreted by the browser, should result in a
 // javascript string that is identical and the same length as the input |str|.
-BASE_EXPORT void JsonDoubleQuote(const std::string& str,
+BASE_EXPORT void JsonDoubleQuote(const StringPiece& str,
                                  bool put_in_quotes,
                                  std::string* dst);
 
 // Same as above, but always returns the result double quoted.
-BASE_EXPORT std::string GetDoubleQuotedJson(const std::string& str);
+BASE_EXPORT std::string GetDoubleQuotedJson(const StringPiece& str);
 
-BASE_EXPORT void JsonDoubleQuote(const string16& str,
+BASE_EXPORT void JsonDoubleQuote(const StringPiece16& str,
                                  bool put_in_quotes,
                                  std::string* dst);
 
 // Same as above, but always returns the result double quoted.
-BASE_EXPORT std::string GetDoubleQuotedJson(const string16& str);
+BASE_EXPORT std::string GetDoubleQuotedJson(const StringPiece16& str);
 
 }  // namespace base
 

base/json/string_escape_unittest.cc

@@ -25,9 +25,13 @@ const struct json_narrow_test_data {
 
 TEST(StringEscapeTest, JsonDoubleQuoteNarrow) {
   for (size_t i = 0; i < arraysize(json_narrow_cases); ++i) {
-    std::string in = json_narrow_cases[i].to_escape;
+    const char* in_ptr = json_narrow_cases[i].to_escape;
+    std::string in_str = in_ptr;
     std::string out;
-    JsonDoubleQuote(in, false, &out);
+    JsonDoubleQuote(in_ptr, false, &out);
+    EXPECT_EQ(std::string(json_narrow_cases[i].escaped), out);
+    out.erase();
+    JsonDoubleQuote(in_str, false, &out);
     EXPECT_EQ(std::string(json_narrow_cases[i].escaped), out);
   }