Adds a basic offline check to InstallableManager.

chrome/browser/installable/installable_logging.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/installable/installable_logging.h"
 
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 46 matching lines @@
     "the specified application platform is not supported on Android";
 static const char kNoIdSpecifiedMessage[] =
     "no Play store ID provided";
 static const char kIdsDoNotMatchMessage[] =
     "a Play Store app URL and Play Store ID were specified in the manifest, "
     "but they do not match";
 static const char kUrlNotSupportedForWebApkMessage[] =
     "a URL in the web manifest contains a username, password, or port";
 static const char kInIncognitoMessage[] =
     "the page is loaded in an incognito window";
-
+static const char kNoServiceWorkerFetchHandlerMessage[] =
+    "a fetch handler is not present in the service worker";

[dominickn, 2017/03/16 06:21:56]

Nit: let's just make this "the page does not work offline". That way this
message will stay true over time as we ratchet up the checks.

[piotrs, 2017/03/17 02:21:37]

Like it, thanks. Also it doesn't expose our internal (and arguably not very
comprehensive) check.

 }  // namespace
 
 void LogErrorToConsole(content::WebContents* web_contents,
                        InstallableStatusCode code,
                        const std::string& param) {
   if (!web_contents)
     return;
 
   content::ConsoleMessageLevel severity = content::CONSOLE_MESSAGE_LEVEL_ERROR;
   const char* pattern = nullptr;
@@ skipping 66 matching lines @@
       break;
     case IDS_DO_NOT_MATCH:
       pattern = kIdsDoNotMatchMessage;
       break;
     case URL_NOT_SUPPORTED_FOR_WEBAPK:
       pattern = kUrlNotSupportedForWebApkMessage;
       break;
     case IN_INCOGNITO:
       pattern = kInIncognitoMessage;
       break;
+    case NO_SERVICE_WORKER_FETCH_HANDLER:
+      pattern = kNoServiceWorkerFetchHandlerMessage;
+      break;
   }
 
   if (!pattern)
     return;
   std::string message = param.empty() ?
       pattern : base::StringPrintf(pattern, param.c_str());
   web_contents->GetMainFrame()->AddMessageToConsole(
       severity, GetMessagePrefix() + message);
 }