Web MIDI: add RequestMIDISysExPermission to BrowserContext

content/public/test/test_browser_context.cc

Index: content/public/test/test_browser_context.cc
diff --git a/content/public/test/test_browser_context.cc b/content/public/test/test_browser_context.cc
index 05f40e842e443b5156c2b5b948ed71a368391ac6..3e909c28f801c9fb4cc1e09f77c498e724183ed6 100644
--- a/content/public/test/test_browser_context.cc
+++ b/content/public/test/test_browser_context.cc
@@ -99,6 +99,15 @@ TestBrowserContext::GetMediaRequestContextForStoragePartition(
   return NULL;
 }
 
+void TestBrowserContext::RequestMIDISysExPermission(
+      int render_process_id,
+      int render_view_id,
+      const GURL& requesting_frame,
+      const MIDISysExPermissionCallback& callback) {
+  // Always reject requests for testing.
+  callback.Run(false);
+}
+
 ResourceContext* TestBrowserContext::GetResourceContext() {
   if (!resource_context_)
     resource_context_.reset(new MockResourceContext());