<webview>: First stab at implementing media permission request for guests.

chrome/renderer/extensions/dispatcher.cc

Index: chrome/renderer/extensions/dispatcher.cc
diff --git a/chrome/renderer/extensions/dispatcher.cc b/chrome/renderer/extensions/dispatcher.cc
index b54f225842bc7a42da85d47ca542c9ef3d3f3f59..30d6ed6c9e0bd767bc79d1fb7f2f71e3d6b277ad 100644
--- a/chrome/renderer/extensions/dispatcher.cc
+++ b/chrome/renderer/extensions/dispatcher.cc
@@ -692,6 +692,8 @@ void Dispatcher::PopulateSourceMap() {
   // Platform app sources that are not API-specific..
   source_map_.RegisterSource("tagWatcher", IDR_TAG_WATCHER_JS);
   source_map_.RegisterSource("webview", IDR_WEB_VIEW_JS);
+  source_map_.RegisterSource("webview.experimentalAPI",
+                             IDR_WEB_VIEW_EXPERIMENTAL_API_JS);
   source_map_.RegisterSource("denyWebview", IDR_WEB_VIEW_DENY_JS);
   source_map_.RegisterSource("platformApp", IDR_PLATFORM_APP_JS);
   source_map_.RegisterSource("injectAppTitlebar", IDR_INJECT_APP_TITLEBAR_JS);
@@ -824,6 +826,10 @@ void Dispatcher::DidCreateScriptContext(
   if (context_type == Feature::BLESSED_EXTENSION_CONTEXT) {
     bool has_permission = extension->HasAPIPermission(APIPermission::kWebView);
     module_system->Require(has_permission ? "webview" : "denyWebview");
+    if (has_permission &&
+        extension->HasAPIPermission(APIPermission::kExperimental)) {
+      module_system->Require("webview.experimentalAPI");
+    }
   }
 
   context->set_module_system(module_system.Pass());