Updating JSON Schema Compiler to add description field to schemas.

chrome/common/extensions/api/tts_engine.json

Index: chrome/common/extensions/api/tts_engine.json
diff --git a/chrome/common/extensions/api/tts_engine.json b/chrome/common/extensions/api/tts_engine.json
index 4c6bb264dd533cf6b26a1d63c136209b07545ff4..8dd72b13551408bc75b42c1646eff742393ec82a 100644
--- a/chrome/common/extensions/api/tts_engine.json
+++ b/chrome/common/extensions/api/tts_engine.json
@@ -5,6 +5,7 @@
 [
   {
     "namespace": "ttsEngine",
+    "description": "Use the <code>chrome.ttsEngine</code> API to implement a text-to-speech(TTS) engine using an extension. If your extension registers using this API, it will receive events containing an utterance to be spoken and other parameters when any extension or packaged app uses the <a href='tts.html'>tts</a> API to generate speech. Your extension can then use any available web technology to synthesize and output the speech, and send events back to the calling function to report the status.",
     "functions": [
       {
         "name": "sendTtsEvent",