Port more String and HashMap usages

sky/engine/tonic/dart_exception_factory.cc

Index: sky/engine/tonic/dart_exception_factory.cc
diff --git a/sky/engine/tonic/dart_exception_factory.cc b/sky/engine/tonic/dart_exception_factory.cc
index e439a45393cad0e5d3af5b42fedb5ecc60d850fa..62d9de99cedac56232097888a0cffc6ae231b3b7 100644
--- a/sky/engine/tonic/dart_exception_factory.cc
+++ b/sky/engine/tonic/dart_exception_factory.cc
@@ -6,7 +6,6 @@
 
 #include "sky/engine/tonic/dart_converter.h"
 #include "sky/engine/tonic/dart_builtin.h"
-#include "sky/engine/wtf/text/StringBuilder.h"
 
 namespace blink {
 
@@ -18,23 +17,35 @@ DartExceptionFactory::~DartExceptionFactory() {
 }
 
 Dart_Handle DartExceptionFactory::CreateNullArgumentException(int index) {
-  StringBuilder message;
-  message.appendLiteral("Argument ");
-  message.appendNumber(index);
-  message.appendLiteral(" cannot be null.");
-  return CreateException("ArgumentError", message.toString());
+  const char* kArgument = "Argument ";
+  const intptr_t kArgumentLen = strlen(kArgument);
+  const char* kCannotBeNull = " cannot be null.";
+  const intptr_t kCannotBeNullLen = strlen(kCannotBeNull);
+  const std::string index_string = std::to_string(index);
+  std::vector<char> message;
+  message.reserve(kArgumentLen + kCannotBeNullLen + index_string.length() + 1);
+  std::copy(kArgument,
+            kArgument + kArgumentLen,
+            back_inserter(message));
+  std::copy(index_string.c_str(),
+            index_string.c_str() + index_string.length(),
+            back_inserter(message));
+  std::copy(kCannotBeNull,
+            kCannotBeNull + kCannotBeNullLen + 1,  // +1 for '\0' character.
+            back_inserter(message));
+  return CreateException("ArgumentError", message.data());

[abarth-chromium, 2015/07/16 00:02:24]

So ugly...

Sorry to get hung up on this issue.  IMHO, the right thing to do here is to make
a StdStringBuilder class that can build std::strings in a reasonable way.  If
you feel like that's out of scope for this CL, I think it would be ok to go back
to what you had before with a TODO about using a StdStringBuilder instead.

[Cutch, 2015/07/16 14:31:02]

Done. We can address any follow up comments you have on StdStringBuilder in a
follow up CL.

 }
 
-Dart_Handle DartExceptionFactory::CreateException(const String& class_name,
-                                                  const String& message) {
+Dart_Handle DartExceptionFactory::CreateException(const std::string& class_name,
+                                                  const std::string& message) {
   if (core_library_.is_empty()) {
     Dart_Handle library = DartBuiltin::LookupLibrary("dart:core");
     core_library_.Set(dart_state_, library);
   }
 
   Dart_Handle exception_class = Dart_GetType(
-      core_library_.value(), StringToDart(dart_state_, class_name), 0, 0);
-  Dart_Handle message_handle = StringToDart(dart_state_, message);
+      core_library_.value(), StdStringToDart(class_name), 0, 0);
+  Dart_Handle message_handle = StdStringToDart(message);
   return Dart_New(exception_class, Dart_EmptyString(), 1, &message_handle);
 }