Fixing transparent pixels appearing black when rendered for the context menu.

chrome/browser/ui/tab_contents/core_tab_helper.cc

Index: chrome/browser/ui/tab_contents/core_tab_helper.cc
diff --git a/chrome/browser/ui/tab_contents/core_tab_helper.cc b/chrome/browser/ui/tab_contents/core_tab_helper.cc
index ac3e496fd7acbe8229201729ea10088161b315aa..c743981957ab67b1bf11f9bab4c798f8baf07b45 100644
--- a/chrome/browser/ui/tab_contents/core_tab_helper.cc
+++ b/chrome/browser/ui/tab_contents/core_tab_helper.cc
@@ -54,6 +54,7 @@ namespace {
 const int kImageSearchThumbnailMinSize = 300 * 300;
 const int kImageSearchThumbnailMaxWidth = 600;
 const int kImageSearchThumbnailMaxHeight = 600;
+const int kUsingPNGCodec = false;
 
 }  // namespace
 
@@ -119,6 +120,7 @@ void CoreTabHelper::SearchByImageInNewTab(
   thumbnail_capturer_proxy->RequestThumbnailForContextNode(
       kImageSearchThumbnailMinSize,
       gfx::Size(kImageSearchThumbnailMaxWidth, kImageSearchThumbnailMaxHeight),
+      kUsingPNGCodec,
       base::Bind(&CoreTabHelper::DoSearchByImageInNewTab,
                  weak_factory_.GetWeakPtr(), base::Passed(&thumbnail_capturer),
                  src_url));