[Icons NTP] Make local NTP large icons URL match device resolution.

For chrome.embeddedSearch.searchBox.getMostVisitedItemData(rid), the
largeIconUrl and fallbackIconUrl items now requests icon sizes depending
on window.devicePixelWidth, rather than the fixed 96. The task has to be
split between C++ and JS code due to data availability.

BUG=479774

Review URL: https://codereview.chromium.org/1101663004

Cr-Commit-Position: refs/heads/master@{#326640}

2 files changed, 28 insertions, 29 deletions

diff --git a/chrome/renderer/resources/extensions/searchbox_api.js b/chrome/renderer/resources/extensions/searchbox_api.js
index a158ac4..f6e5b3e 100644
--- a/chrome/renderer/resources/extensions/searchbox_api.js
+++ b/chrome/renderer/resources/extensions/searchbox_api.js
@@ -48,7 +48,21 @@ if (!chrome.embeddedSearch) {
       // This method is restricted to chrome-search://most-visited pages by
       // checking the invoking context's origin in searchbox_extension.cc.
       this.getMostVisitedItemData = function(restrictedId) {
-        return GetMostVisitedItemData(restrictedId);
+        var item = GetMostVisitedItemData(restrictedId);
+        if (item) {
+          var sizeInPx = Math.floor(48 * window.devicePixelRatio + 0.5);
+          // Populate large icon and fallback icon data, if they exist. We'll
+          // render everything here, once these become available by default.
+          if (item.largeIconUrl) {
+            item.largeIconUrl +=
+                sizeInPx + "/" + item.renderViewId + "/" + item.rid;
+          }
+          if (item.fallbackIconUrl) {
+            item.fallbackIconUrl +=
+                sizeInPx + ",,,,/" + item.renderViewId + "/" + item.rid;
+          }
+        }
+        return item;
       };
 
       this.paste = function(value) {
@@ -102,13 +116,16 @@ if (!chrome.embeddedSearch) {
         var mostVisitedItems = GetMostVisitedItems();
         for (var i = 0, item; item = mostVisitedItems[i]; ++i) {
           item.faviconUrl = GenerateFaviconURL(item.renderViewId, item.rid);
+
           // These properties are private data and should not be returned to
           // the page. They are only accessible via getMostVisitedItemData().
-          item.url = null;
-          item.title = null;
-          item.domain = null;
-          item.direction = null;
-          item.renderViewId = null;
+          delete item.url;
+          delete item.title;
+          delete item.domain;
+          delete item.direction;
+          delete item.renderViewId;
+          delete item.largeIconUrl;
+          delete item.fallbackIconUrl;
         }
         return mostVisitedItems;
       }
diff --git a/chrome/renderer/searchbox/searchbox_extension.cc b/chrome/renderer/searchbox/searchbox_extension.cc
index c9e69b3..727ed9c 100644
--- a/chrome/renderer/searchbox/searchbox_extension.cc
+++ b/chrome/renderer/searchbox/searchbox_extension.cc
@@ -117,27 +117,6 @@ v8::Handle<v8::String> GenerateThumbnailURL(
           "chrome-search://thumb/%d/%d", render_view_id, most_visited_item_id));
 }
 
-v8::Handle<v8::String> GenerateLargeIconURL(
-    v8::Isolate* isolate,
-    int render_view_id,
-    InstantRestrictedID most_visited_item_id) {
-  const int kIconSize = 96;  // To support high DPI; on screen it's 48 dp.
-  return UTF8ToV8String(
-      isolate,
-      base::StringPrintf("chrome-search://large-icon/%d/%d/%d",
-                         kIconSize, render_view_id, most_visited_item_id));
-}
-
-v8::Handle<v8::String> GenerateFallbackIconURL(
-    v8::Isolate* isolate,
-    int render_view_id,
-    InstantRestrictedID most_visited_item_id) {
-  return UTF8ToV8String(
-      isolate,
-      base::StringPrintf("chrome-search://fallback-icon/,,,,1/%d/%d",
-                         render_view_id, most_visited_item_id));
-}
-
 // Populates a Javascript MostVisitedItem object from |mv_item|.
 // NOTE: Includes "url", "title" and "domain" which are private data, so should
 // not be returned to the Instant page. These should be erased before returning
@@ -178,10 +157,13 @@ v8::Handle<v8::Object> GenerateMostVisitedItem(
   if (IsIconNTPEnabled()) {
     // Update website http://www.chromium.org/embeddedsearch when we make this
     // permanent.
+    // Large icon size is 48px * window.devicePixelRatio. This is easier to set
+    // from JS, where IsIconNTPEnabled() is not available. So we add stubs
+    // here, and let JS fill in details.
     obj->Set(v8::String::NewFromUtf8(isolate, "largeIconUrl"),
-             GenerateLargeIconURL(isolate, render_view_id, restricted_id));
+             v8::String::NewFromUtf8(isolate, "chrome-search://large-icon/"));
     obj->Set(v8::String::NewFromUtf8(isolate, "fallbackIconUrl"),
-             GenerateFallbackIconURL(isolate, render_view_id, restricted_id));
+        v8::String::NewFromUtf8(isolate, "chrome-search://fallback-icon/"));
   }
   obj->Set(v8::String::NewFromUtf8(isolate, "title"),
            UTF16ToV8String(isolate, title));