Remove unnecessary NSString conversions in sandbox_mac.mm.

content/common/sandbox_mac.mm

Index: content/common/sandbox_mac.mm
diff --git a/content/common/sandbox_mac.mm b/content/common/sandbox_mac.mm
index 9994f45136f3b244104e39ad990abda67b9ad8e7..ccfe86710257cc93502372c147b2c2ac4f940e46 100644
--- a/content/common/sandbox_mac.mm
+++ b/content/common/sandbox_mac.mm
@@ -359,8 +359,8 @@ void Sandbox::SandboxWarmup(int sandbox_type) {
 }
 
 // Load the appropriate template for the given sandbox type.
-// Returns the template as an NSString or nil on error.
-NSString* LoadSandboxTemplate(int sandbox_type) {
+// Returns the template as a string or an empty string on error.
+std::string LoadSandboxTemplate(int sandbox_type) {
   // We use a custom sandbox definition to lock things down as tightly as
   // possible.
   int sandbox_profile_resource_id = -1;
@@ -390,7 +390,7 @@ NSString* LoadSandboxTemplate(int sandbox_type) {
   if (sandbox_definition.empty()) {
     LOG(FATAL) << "Failed to load the sandbox profile (resource id "
                << sandbox_profile_resource_id << ")";
-    return nil;
+    return std::string();
   }
 
   base::StringPiece common_sandbox_definition =
@@ -398,21 +398,13 @@ NSString* LoadSandboxTemplate(int sandbox_type) {
           IDR_COMMON_SANDBOX_PROFILE, ui::SCALE_FACTOR_NONE);
   if (common_sandbox_definition.empty()) {
     LOG(FATAL) << "Failed to load the common sandbox profile";
-    return nil;
+    return std::string();
   }
 
-  base::scoped_nsobject<NSString> common_sandbox_prefix_data(
-      [[NSString alloc] initWithBytes:common_sandbox_definition.data()
-                               length:common_sandbox_definition.length()
-                             encoding:NSUTF8StringEncoding]);
-
-  base::scoped_nsobject<NSString> sandbox_data(
-      [[NSString alloc] initWithBytes:sandbox_definition.data()
-                               length:sandbox_definition.length()
-                             encoding:NSUTF8StringEncoding]);
-
   // Prefix sandbox_data with common_sandbox_prefix_data.
-  return [common_sandbox_prefix_data stringByAppendingString:sandbox_data];
+  std::string sandbox_profile = common_sandbox_definition.as_string();
+  sandbox_definition.AppendToString(&sandbox_profile);
+  return sandbox_profile;
 }
 
 // Turns on the OS X sandbox for this process.
@@ -428,12 +420,12 @@ bool Sandbox::EnableSandbox(int sandbox_type,
         << "Only SANDBOX_TYPE_UTILITY allows a custom directory parameter.";
   }
 
-  NSString* sandbox_data = LoadSandboxTemplate(sandbox_type);
-  if (!sandbox_data) {
+  std::string sandbox_data = LoadSandboxTemplate(sandbox_type);
+  if (sandbox_data.empty()) {
     return false;
   }
 
-  SandboxCompiler compiler([sandbox_data UTF8String]);
+  SandboxCompiler compiler(sandbox_data);
 
   if (!allowed_dir.empty()) {
     // Add the sandbox parameters necessary to access the given directory.