Remove the use of the background transport for transparent Mac plugins.

Since CG preserves alpha, and plugins don't composite onto pages manually, we don't need the extra buffer on the Mac.

BUG=41194
TEST=Transparent plugins (mostly Flash) should continue to work normally.

Review URL: http://codereview.chromium.org/1549035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44265 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 5 deletions

diff --git a/chrome/plugin/webplugin_proxy.cc b/chrome/plugin/webplugin_proxy.cc
index 273cd95..ac04589 100644
--- a/chrome/plugin/webplugin_proxy.cc
+++ b/chrome/plugin/webplugin_proxy.cc
@@ -366,11 +366,7 @@ void WebPluginProxy::Paint(const gfx::Rect& rect) {
   // sense, so this should only be used for pointer comparisons.
   CGContextRef saved_context_weak = windowless_context_.get();
 
-  if (!background_context_.get()) {
-    CGContextSetFillColorWithColor(windowless_context_,
-                                   CGColorGetConstantColor(kCGColorBlack));
-    CGContextFillRect(windowless_context_, rect.ToCGRect());
-  } else {
+  if (background_context_.get()) {
     scoped_cftyperef<CGImageRef> image(
         CGBitmapContextCreateImage(background_context_));
     CGRect source_rect = rect.ToCGRect();
@@ -379,6 +375,8 @@ void WebPluginProxy::Paint(const gfx::Rect& rect) {
     scoped_cftyperef<CGImageRef> sub_image(
         CGImageCreateWithImageInRect(image, source_rect));
     CGContextDrawImage(windowless_context_, rect.ToCGRect(), sub_image);
+  } else {
+    CGContextClearRect(windowless_context_, rect.ToCGRect());
   }
   CGContextClipToRect(windowless_context_, rect.ToCGRect());
   delegate_->Paint(windowless_context_, rect);