Handle integer -0 as 0 in extensions

-0 is treated as double 0.0f in V8. This makes GetAsInteger()
return -0 is not an integer type. Extension APIs with integer parameters
will fail to get the value using GetAsInteger(). This CL convert integer
-0 to integer 0.

BUG=471011

Review URL: https://codereview.chromium.org/1126983009

Cr-Commit-Position: refs/heads/master@{#329860}

extensions/renderer/resources/schema_utils.js

@@ -118,6 +118,9 @@ function normalizeArgumentsAndValidate(args, funDef) {
   var normalizedArgs = [];
   var ai = 0;
   for (var si = 0; si < definedSignature.length; si++) {
+    // Handle integer -0 as 0.
+    if (JSONSchemaValidator.getType(args[ai]) === "integer" && args[ai] === 0)
+      args[ai] = 0;
     if (definedSignature[si] === resolvedSignature[ai])
       $Array.push(normalizedArgs, args[ai++]);
     else