[inspector] Fix and refactor String16

src/inspector/v8-debugger-agent-impl.cc

Index: src/inspector/v8-debugger-agent-impl.cc
diff --git a/src/inspector/v8-debugger-agent-impl.cc b/src/inspector/v8-debugger-agent-impl.cc
index ab4e349909865e93c5c2ecc23f888dd16a45e6da..224ae282c4d70af974f35a094e05b28c2b46feaa 100644
--- a/src/inspector/v8-debugger-agent-impl.cc
+++ b/src/inspector/v8-debugger-agent-impl.cc
@@ -76,8 +76,14 @@ static String16 breakpointIdSuffix(
 static String16 generateBreakpointId(
     const String16& scriptId, int lineNumber, int columnNumber,
     V8DebuggerAgentImpl::BreakpointSource source) {
-  return scriptId + ":" + String16::fromInteger(lineNumber) + ":" +
-         String16::fromInteger(columnNumber) + breakpointIdSuffix(source);
+  String16Builder builder;

[dgozman, 2016/11/15 15:32:25]

Just curious why builder and not concat with fromInteger()?

[Clemens Hammacher, 2016/11/15 17:00:44]

Performance ;)

+  builder.append(scriptId);
+  builder.append(':');
+  builder.appendNumber(lineNumber);
+  builder.append(':');
+  builder.appendNumber(columnNumber);
+  builder.append(breakpointIdSuffix(source));
+  return builder.toString();
 }
 
 static bool positionComparator(const std::pair<int, int>& a,