Don't repaint tab when TabRenderData hasn't changed.

chrome/browser/ui/views/tabs/tab_renderer_data.h

Index: chrome/browser/ui/views/tabs/tab_renderer_data.h
diff --git a/chrome/browser/ui/views/tabs/tab_renderer_data.h b/chrome/browser/ui/views/tabs/tab_renderer_data.h
index ce6b3383b66ce61afc5e2809124edefa32a4412c..43962dfdffce15bfd2219219a9c91a50fc2f4464 100644
--- a/chrome/browser/ui/views/tabs/tab_renderer_data.h
+++ b/chrome/browser/ui/views/tabs/tab_renderer_data.h
@@ -41,6 +41,24 @@ struct TabRendererData {
             crashed_status == base::TERMINATION_STATUS_ABNORMAL_TERMINATION);
   }
 
+  // Returns true if the TabRendererData is same as given |data|. Two favicons
+  // are considered equals if two SkBitmaps point to the same SkPixelRef object.
+  bool Equals(const TabRendererData& data) {
+    return
+        favicon.pixelRef() &&
+        favicon.pixelRef() == data.favicon.pixelRef() &&
+        favicon.pixelRefOffset() == data.favicon.pixelRefOffset() &&

[oshima, 2011/02/26 00:18:29]

Brett, I'm assuming that chrome does not change
the data in SkPixelRef for favicons. Scott told me that you may know if my
assumption is correct. Let me know if you don't know and I'll find someone else.

[brettw, 2011/02/26 03:26:04]

Good question. This is *probably* OK but I'm not sure. I'm adding Mike Reed to
the review who will be able to tell us definitively.

+        network_state == data.network_state &&
+        title == data.title &&
+        loading == data.loading &&
+        crashed_status == data.crashed_status &&
+        off_the_record == data.off_the_record &&
+        show_icon == data.show_icon &&
+        mini == data.mini &&
+        blocked == data.blocked &&
+        app == data.app;
+  }
+
   SkBitmap favicon;
   NetworkState network_state;
   string16 title;