Update Flash plugin metadata version to latest versions.

chrome/browser/resources/plugin_metadata/plugins_mac.json

 {
-  "x-version": 7,
+  "x-version": 8,
   "google-talk": {
     "mime_types": [
     ],
     "versions": [
       {
         "version": "0",
         "status": "requires_authorization",
         "comment": "'Google Talk Plugin' and 'Google Talk Plugin Video Accelerator' use two completely different versioning schemes, so we can't define a minimum version."
       }
     ],
@@ skipping 95 matching lines @@
     "help_url": "https://support.google.com/chrome/?p=plugin_real",
     "group_name_matcher": "*RealPlayer*"
   },
   "adobe-flash-player": {
     "mime_types": [
       "application/futuresplash",
       "application/x-shockwave-flash"
     ],
     "versions": [
       {
-        "version": "16.0.0.235",
+        "version": "16.0.0.305",
         "status": "requires_authorization",
-        "reference": "https://helpx.adobe.com/security/products/flash-player/apsb14-27.html"
+        "reference": "https://helpx.adobe.com/security/products/flash-player/apsb15-04.html"
       }
     ],
     "lang": "en-US",
     "name": "Adobe Flash Player",
     "url": "http://get.adobe.com/flashplayer/",
     "help_url": "https://support.google.com/chrome/?p=plugin_flash",
     "displayurl": true,
     "group_name_matcher": "*Shockwave Flash*"
   },
   "adobe-shockwave": {
@@ skipping 179 matching lines @@
         "status": "requires_authorization",
         "comment": "We do not track version information for the Google Earth Plugin."
       }
     ],
     "lang": "en-US",
     "name": "Google Earth",
     "url": "http://www.google.com/earth/explore/products/plugin.html",
     "group_name_matcher": "*Google Earth*"
   }
 }