Port messages sent by WebIDBFactoryImpl to Mojo.

content/common/BUILD.gn

Index: content/common/BUILD.gn
diff --git a/content/common/BUILD.gn b/content/common/BUILD.gn
index d8e7df50442aac362156ba9b5bd8c25347013eed..73aa7e398fbec86db3deaad2c3664d3970704d68 100644
--- a/content/common/BUILD.gn
+++ b/content/common/BUILD.gn
@@ -149,8 +149,11 @@ source_set("common") {
     "indexed_db/indexed_db_key_range.cc",
     "indexed_db/indexed_db_key_range.h",
     "indexed_db/indexed_db_messages.h",
+    "indexed_db/indexed_db_metadata.cc",
+    "indexed_db/indexed_db_metadata.h",
     "indexed_db/indexed_db_param_traits.cc",
     "indexed_db/indexed_db_param_traits.h",
+    "indexed_db/indexed_db_struct_traits.h",
     "input/event_with_latency_info.cc",
     "input/event_with_latency_info.h",
     "input/gesture_event_stream_validator.cc",
@@ -550,11 +553,15 @@ mojom("mojo_bindings") {
   # This interface is internal to content.
   visibility = [ "//content/*" ]
 
+  # indexed_db.mojom uses a native typemap that is not available in Java.
+  cpp_only = true
+
   sources = [
     "associated_interfaces.mojom",
     "child_memory_coordinator.mojom",
     "frame.mojom",
     "image_downloader/image_downloader.mojom",
+    "indexed_db/indexed_db.mojom",
     "leveldb_wrapper.mojom",
     "media/media_devices.mojom",
     "memory_coordinator.mojom",