[Extensions Bindings] Fix getPlatform() method

extensions/renderer/process_info_native_handler.cc

Index: extensions/renderer/process_info_native_handler.cc
diff --git a/extensions/renderer/process_info_native_handler.cc b/extensions/renderer/process_info_native_handler.cc
index 545a21274dc0fac29a7e135270d69ba7c21cfa21..32a15b8a7d61cd4299b408514d19dc419f3c07ed 100644
--- a/extensions/renderer/process_info_native_handler.cc
+++ b/extensions/renderer/process_info_native_handler.cc
@@ -8,7 +8,9 @@
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "extensions/renderer/bindings/api_binding_util.h"
 #include "extensions/renderer/script_context.h"
+#include "gin/converter.h"
 
 namespace extensions {
 
@@ -48,6 +50,9 @@ ProcessInfoNativeHandler::ProcessInfoNativeHandler(
   RouteFunction(
       "HasSwitch",
       base::Bind(&ProcessInfoNativeHandler::HasSwitch, base::Unretained(this)));
+  RouteFunction("GetPlatform",
+                base::Bind(&ProcessInfoNativeHandler::GetPlatform,
+                           base::Unretained(this)));
 }
 
 void ProcessInfoNativeHandler::GetExtensionId(
@@ -95,4 +100,11 @@ void ProcessInfoNativeHandler::HasSwitch(
   args.GetReturnValue().Set(v8::Boolean::New(args.GetIsolate(), has_switch));
 }
 
+void ProcessInfoNativeHandler::GetPlatform(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  CHECK_EQ(0, args.Length());
+  args.GetReturnValue().Set(
+      gin::StringToSymbol(args.GetIsolate(), binding::GetPlatformString()));
+}
+
 }  // namespace extensions