[OfflinePages] Improve visiblity/handling of "Loading not started" case

chrome/browser/android/offline_pages/prerendering_loader.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/android/offline_pages/prerendering_loader.h"
 
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 77 matching lines @@
 }
 
 bool PrerenderingLoader::LoadPage(const GURL& url,
                                   const LoadPageCallback& callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   if (!IsIdle()) {
     DVLOG(1)
         << "WARNING: Existing request in progress or waiting for StopLoading()";
     return false;
   }
-  if (!CanPrerender())
-    return false;
 
   // Create a WebContents instance to define and hold a SessionStorageNamespace
   // for this load request.
   DCHECK(!session_contents_.get());
   std::unique_ptr<content::WebContents> new_web_contents(
       content::WebContents::Create(
           content::WebContents::CreateParams(browser_context_)));
   content::SessionStorageNamespace* sessionStorageNamespace =
       new_web_contents->GetController().GetDefaultSessionStorageNamespace();
   gfx::Size renderWindowSize = new_web_contents->GetContainerBounds().size();
@@ skipping 11 matching lines @@
   session_contents_.swap(new_web_contents);
   state_ = State::LOADING;
   return true;
 }
 
 void PrerenderingLoader::StopLoading() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   CancelPrerender();
 }
 
-bool PrerenderingLoader::CanPrerender() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  return adapter_->CanPrerender();
-}
-
 bool PrerenderingLoader::IsIdle() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return state_ == State::IDLE;
 }
 
 bool PrerenderingLoader::IsLoaded() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return state_ == State::LOADED;
 }
 
@@ skipping 112 matching lines @@
 void PrerenderingLoader::CancelPrerender() {
   if (adapter_->IsActive()) {
     adapter_->DestroyActive();
   }
   snapshot_controller_.reset(nullptr);
   session_contents_.reset(nullptr);
   state_ = State::IDLE;
 }
 
 }  // namespace offline_pages