Improve layout for bookmark-apps. Add a treatment for small icons.

chrome/browser/ui/webui/extension_icon_source.cc

Index: chrome/browser/ui/webui/extension_icon_source.cc
diff --git a/chrome/browser/ui/webui/extension_icon_source.cc b/chrome/browser/ui/webui/extension_icon_source.cc
index 78c7b27b8f8889f3e86cccd4b6de25549d54f9bf..6a52ba6540d1c06e025e6466d92c9f8cf2a823cd 100644
--- a/chrome/browser/ui/webui/extension_icon_source.cc
+++ b/chrome/browser/ui/webui/extension_icon_source.cc
@@ -75,10 +75,16 @@ ExtensionIconSource::~ExtensionIconSource() {
 GURL ExtensionIconSource::GetIconURL(const Extension* extension,
                                      Extension::Icons icon_size,
                                      ExtensionIconSet::MatchType match,
-                                     bool grayscale) {
+                                     bool grayscale,
+                                     bool* exists) {
+  if (exists)
+    *exists = true;
   if (extension->id() == extension_misc::kWebStoreAppId)
     return GURL("chrome://theme/IDR_WEBSTORE_ICON");
 
+  if (exists && extension->GetIconURL(icon_size, match) == GURL())
+    *exists = false;
+
   GURL icon_url(base::StringPrintf("%s%s/%d/%d%s",
                                    chrome::kChromeUIExtensionIconURL,
                                    extension->id().c_str(),