[Icons NTP] Enable Large Icon URL storage and image fetching (Touch Icons only), behind flag.

chrome/browser/favicon/favicon_tab_helper.cc

 // Copyright (c) 2012 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/favicon/favicon_tab_helper.h"
 
+#include "base/metrics/field_trial.h"
+#include "base/strings/string_util.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/favicon/chrome_favicon_client.h"
 #include "chrome/browser/favicon/chrome_favicon_client_factory.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/search.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/url_constants.h"
 #include "components/favicon/core/browser/favicon_handler.h"
@@ skipping 16 matching lines @@
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_skia_rep.h"
 
 using content::FaviconStatus;
 using content::NavigationController;
 using content::NavigationEntry;
 using content::WebContents;
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(FaviconTabHelper);
 
+namespace {
+
+// Returns whether icon NTP is enabled.
+bool IsIconNTPEnabled() {

[sky, 2015/05/06 19:29:05]

Will this ever be used on android?

[huangs, 2015/05/06 19:59:14]

Currently it isn't, and likely Android will do things differently but we have to
verify that.

Should we wrap this under !defined(OS_ANDROID) then, and do something similar to
download_largest_icon in line 59?

+  return StartsWithASCII(base::FieldTrialList::FindFullName("IconNTP"),
+                         "Enabled", true);
+}
+
+}  // namespace
+
 FaviconTabHelper::FaviconTabHelper(WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       profile_(Profile::FromBrowserContext(web_contents->GetBrowserContext())) {
   client_ = ChromeFaviconClientFactory::GetForProfile(profile_);
 #if defined(OS_ANDROID) || defined(OS_IOS)
   bool download_largest_icon = true;
 #else
   bool download_largest_icon = false;
 #endif
   FaviconService* service = FaviconServiceFactory::GetForProfile(
       profile_, ServiceAccessType::EXPLICIT_ACCESS);
   favicon_handler_.reset(new FaviconHandler(
       service, client_, this, FaviconHandler::FAVICON, download_largest_icon));
   if (chrome::kEnableTouchIcon)
     touch_icon_handler_.reset(new FaviconHandler(
         service, client_, this, FaviconHandler::TOUCH, download_largest_icon));
+  if (IsIconNTPEnabled())

[sky, 2015/05/06 20:13:53]

My concern is more of here. If IsIconNTPEnabled is true on android it would mean
downloading icons twice. I think this should be an else (with a comment).
Otherwise we may end up downloading the same set of icons twice.

[huangs, 2015/05/06 20:33:55]

rogerm@ has considered this, and has a CL to make this cleaner:
https://crrev.com/1118073002/

+    large_icon_handler_.reset(new FaviconHandler(
+        service, client_, this, FaviconHandler::LARGE, true));
 }
 
 FaviconTabHelper::~FaviconTabHelper() {
 }
 
 void FaviconTabHelper::FetchFavicon(const GURL& url) {
   favicon_handler_->FetchFavicon(url);
   if (touch_icon_handler_.get())
     touch_icon_handler_->FetchFavicon(url);
+  if (large_icon_handler_.get())
+    large_icon_handler_->FetchFavicon(url);
 }
 
 gfx::Image FaviconTabHelper::GetFavicon() const {
   // Like GetTitle(), we also want to use the favicon for the last committed
   // entry rather than a pending navigation entry.
   const NavigationController& controller = web_contents()->GetController();
   NavigationEntry* entry = controller.GetTransientEntry();
   if (entry)
     return entry->GetFavicon().image;
 
@@ skipping 215 matching lines @@
   for (size_t i = 0; i < candidates.size(); i++) {
     const content::FaviconURL& candidate = candidates[i];
     favicon_urls.push_back(
         favicon::FaviconURL(candidate.icon_url,
                             ToChromeIconType(candidate.icon_type),
                             candidate.icon_sizes));
   }
   favicon_handler_->OnUpdateFaviconURL(favicon_urls);
   if (touch_icon_handler_.get())
     touch_icon_handler_->OnUpdateFaviconURL(favicon_urls);
+  if (large_icon_handler_.get())
+    large_icon_handler_->OnUpdateFaviconURL(favicon_urls);
 }
 
 void FaviconTabHelper::DidDownloadFavicon(
     int id,
     int http_status_code,
     const GURL& image_url,
     const std::vector<SkBitmap>& bitmaps,
     const std::vector<gfx::Size>& original_bitmap_sizes) {
 
   if (bitmaps.empty() && http_status_code == 404) {
     DVLOG(1) << "Failed to Download Favicon:" << image_url;
     FaviconService* favicon_service = FaviconServiceFactory::GetForProfile(
         profile_->GetOriginalProfile(), ServiceAccessType::IMPLICIT_ACCESS);
     if (favicon_service)
       favicon_service->UnableToDownloadFavicon(image_url);
   }
 
   favicon_handler_->OnDidDownloadFavicon(
       id, image_url, bitmaps, original_bitmap_sizes);
   if (touch_icon_handler_.get()) {
     touch_icon_handler_->OnDidDownloadFavicon(
         id, image_url, bitmaps, original_bitmap_sizes);
   }
+  if (large_icon_handler_.get()) {
+    large_icon_handler_->OnDidDownloadFavicon(
+        id, image_url, bitmaps, original_bitmap_sizes);
+  }
 }