Tell IDB frontend about data loss

content/browser/DEPS

 include_rules = [
   "+content/gpu",  # For gpu_info_collector.h and in-process GPU
   "+content/port/browser",
   "+content/public/browser",
   "+content/child/webkitplatformsupport_impl.h",  # For in-process webkit
   "+media/audio",  # For audio input for speech input feature.
   "+media/base",  # For Android JNI registration.
   "+media/midi",  # For Web MIDI API
   "+sql",
   "+ui/webui",
@@ skipping 16 matching lines @@
   "+third_party/cros_system_api",
 
   "-webkit/child",
   "-webkit/renderer",
 
   # No inclusion of WebKit from the browser, other than strictly enum/POD,
   # header-only types, and some selected common code.
   "-third_party/WebKit",
   "+third_party/WebKit/public/platform/WebGamepads.h",
   "+third_party/WebKit/public/platform/WebGraphicsContext3D.h",
+  "+third_party/WebKit/public/platform/WebIDBCallbacks.h",
   "+third_party/WebKit/public/platform/WebIDBDatabase.h",
   "+third_party/WebKit/public/platform/WebIDBDatabaseException.h",
   "+third_party/WebKit/public/platform/WebIDBKeyPath.h",
   "+third_party/WebKit/public/platform/WebReferrerPolicy.h",
   "+third_party/WebKit/public/platform/WebScreenInfo.h",
   "+third_party/WebKit/public/platform/WebString.h",
   "+third_party/WebKit/public/web/WebCompositionUnderline.h",
   "+third_party/WebKit/public/web/WebConsoleMessage.h",
   "+third_party/WebKit/public/web/WebCursorInfo.h",
   "+third_party/WebKit/public/web/WebDevToolsAgent.h",
@@ skipping 19 matching lines @@
   "!third_party/WebKit/public/web/android/WebInputEventFactory.h",
   "!third_party/WebKit/public/web/gtk/WebInputEventFactory.h",
   "!third_party/WebKit/public/web/linux/WebFontInfo.h",
   "!third_party/WebKit/public/web/mac/WebInputEventFactory.h",
   "!third_party/WebKit/public/web/win/WebInputEventFactory.h",
 
   # DO NOT ADD ANY CHROME OR COMPONENTS INCLUDES HERE!!!
   # See https://sites.google.com/a/chromium.org/dev/developers/content-module
   # for more information.
 ]