<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 879214819d3f693d4b6273129ae0b4d731a9fee5..ad9da2a6a99a00bd6c250c4d904a2585131807b2 100644
--- a/chrome/renderer/extensions/dispatcher.cc
+++ b/chrome/renderer/extensions/dispatcher.cc
@@ -695,6 +695,8 @@ 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.experimental",
+                             IDR_WEB_VIEW_EXPERIMENTAL_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);
@@ -828,6 +830,10 @@ 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 &&
+        Feature::GetCurrentChannel() <= chrome::VersionInfo::CHANNEL_DEV) {
+      module_system->Require("webview.experimental");
+    }
   }
 
   context->set_module_system(module_system.Pass());