[2] Adding a method to PluginFinder to get a PluginInstaller by WebPluginInfo.

chrome/browser/resources/plugin_metadata/plugins_mac.json

 {
   "google-talk": {
     "mime_types": [
     ],
     "versions": [
       {
         "version": "0",
         "status": "up_to_date",
         "comment": "'Google Talk Plugin' and 'Google Talk Plugin Video Accelerator' use two completely different versioning schemes, so we can't define a minimum version."
       }
     ],
-    "name": "Google Talk"
+    "name": "Google Talk",
+    "group_name_matcher": "Google Talk"
   },
   "java-runtime-environment": {
     "mime_types": [
       "application/x-java-applet",
       "application/x-java-applet,version=1.1",
       "application/x-java-applet,version=1.1.1",
       "application/x-java-applet,version=1.1.2",
       "application/x-java-applet,version=1.1.3",
       "application/x-java-applet,version=1.2",
       "application/x-java-applet,version=1.2.1",
@@ skipping 44 matching lines @@
       {
         "version": "14.0.3",
         "status": "requires_authorization",
         "comment": "Lion"
       }
     ],
     "lang": "en-US",
     "name": "Java(TM)",
     "url": "http://java.com/en/download/apple_manual.jsp",
     "help_url": "https://support.google.com/chrome/?p=plugin_java",
-    "displayurl": true
+    "displayurl": true,
+    "group_name_matcher": "Java"
   },
   "realplayer": {
     "mime_types": [
       "audio/vnd.rn-realaudio",
       "video/vnd.rn-realvideo",
       "audio/x-pn-realaudio-plugin",
       "audio/x-pn-realaudio"
     ],
     "versions": [
       {
         "version": "0",
         "status": "requires_authorization",
         "comment": "The Real Player plug-in for mac doesn't expose a version at all."
       }
     ],
     "lang": "en-US",
     "name": "RealPlayer",
     "url": "http://director.real.com/realplayer?type=rpsp_mac",
-    "help_url": "https://support.google.com/chrome/?p=plugin_real"
+    "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": "11.1.102",
         "status": "up_to_date",
         "reference": "http://www.adobe.com/support/security/bulletins/apsb12-03.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
+    "displayurl": true,
+    "group_name_matcher": "Shockwave Flash"
   },
   "adobe-shockwave": {
     "mime_types": [
       "application/x-director"
     ],
     "versions": [
       {
         "version": "11.6.6.636",
         "status": "requires_authorization",
         "reference": "http://www.adobe.com/support/security/bulletins/apsb12-17.html"
       }
     ],
     "lang": "en-US",
     "name": "Adobe Shockwave Player",
     "url": "http://fpdownload.macromedia.com/get/shockwave/default/english/macosx/latest/Shockwave_Installer_Full_64bit.dmg",
-    "help_url": "https://support.google.com/chrome/?p=plugin_shockwave"
+    "help_url": "https://support.google.com/chrome/?p=plugin_shockwave",
+    "group_name_matcher": "Shockwave for Director"
   },
   "apple-quicktime": {
     "mime_types": [
       "application/sdp",
       "application/x-mpeg",
       "application/x-rtsp",
       "application/x-sdp",
       "audio/3ggp",
       "audio/3ggp2",
       "audio/aac",
@@ skipping 43 matching lines @@
     "versions": [
       {
         "version": "7.6.6",
         "status": "requires_authorization"
       }
     ],
     "lang": "en-US",
     "name": "QuickTime Player",
     "url": "http://www.apple.com/quicktime/download/",
     "help_url": "https://support.google.com/chrome/?p=plugin_quicktime",
-    "displayurl": true
+    "displayurl": true,
+    "group_name_matcher": "QuickTime Plug-in"
   },
   "flip4mac": {
     "mime_types": [
       "application/asx",
       "application/x-mplayer2",
       "application/x-ms-wmp",
       "audio/x-ms-wax",
       "audio/x-ms-wma",
       "video/x-ms-asf",
       "video/x-ms-asf-plugin",
       "video/x-ms-wm",
       "video/x-ms-wmv",
       "video/x-ms-wvx"
     ],
     "versions": [
       {
         "version": "2.2.1",
         "status": "requires_authorization"
       }
     ],
     "lang": "en-US",
     "name": "Flip4Mac",
     "url": "http://www.microsoft.com/download/en/confirmation.aspx?id=9442",
     "help_url": "https://support.google.com/chrome/?p=plugin_wmp",
-    "displayurl": true
+    "displayurl": true,
+    "group_name_matcher": "Flip4Mac"
   },
   "divx-player": {
     "mime_types": [
       "video/divx",
       "video/x-matroska"
     ],
     "versions": [
       {
         "version": "2.2",
         "status": "requires_authorization"
       }
     ],
     "lang": "en-US",
     "name": "DivX Web Player",
     "url": "http://www.divx.com/en/downloads/divx/mac",
-    "help_url": "https://support.google.com/chrome/?p=plugin_divx"
+    "help_url": "https://support.google.com/chrome/?p=plugin_divx",
+    "group_name_matcher": "DivX Plus Web Player"
   },
   "silverlight": {
     "mime_types": [
       "application/x-silverlight",
       "application/x-silverlight-2"
     ],
     "versions": [
       {
         "version": "4.1.10111.0",
         "status": "up_to_date",
         "reference": "http://support.microsoft.com/kb/2668562"
       }
     ],
     "lang": "en-US",
     "name": "Silverlight",
     "url": "http://go.microsoft.com/fwlink/?LinkID=149156",
-    "displayurl": true
+    "displayurl": true,
+    "group_name_matcher": "Silverlight"
+  },
+  "google-chrome-pdf": {
+    "mime_types": [
+    ],
+    "versions": [
+      {
+        "version": "0",
+        "status": "up_to_date",
+        "comment": "Chrome PDF Viewer has no version information."
+      }
+    ],
+    "name": "Chrome PDF Viewer",
+    "group_name_matcher": "Chrome PDF Viewer"
   }
 }