Update comments in InstallableManager.

chrome/browser/installable/installable_manager.cc

Index: chrome/browser/installable/installable_manager.cc
diff --git a/chrome/browser/installable/installable_manager.cc b/chrome/browser/installable/installable_manager.cc
index f58783fea652ac86a1891b1e766f4b41b8de54e2..58066c13808b94f01a385bf16bd5fcf4c484b770 100644
--- a/chrome/browser/installable/installable_manager.cc
+++ b/chrome/browser/installable/installable_manager.cc
@@ -22,7 +22,8 @@ const char kPngExtension[] = ".png";
 
 // This constant is the icon size on Android (48dp) multiplied by the scale
 // factor of a Nexus 5 device (3x). For mobile and desktop platforms, a 144px
-// icon is an approximate, appropriate lower bound.
+// icon is an approximate, appropriate lower bound. It is the currently
+// advertised minimum icon size for triggering banners.
 // TODO(dominickn): consolidate with minimum_icon_size_in_dp across platforms.
 const int kIconMinimumSizeInPx = 144;