Improve plugin performance on the Mac

This makes a few changes:
- Switch to memcpy instead of CG drawing to copy pixels from the transport bitmap to the backing bitmap (this is a substantial perf win).
- Send transparancy information to the WebPluginDelegate, since it's no longer equivalent to not having a background DIB on the Mac (and likely on the other platforms in the future).
- Don't clear the transport DIB for non-transparent plugins, since they will be drawing over whatever is there anyway.

BUG=41340
TEST=Both transparent and non-transparent plugins should continue to draw correctly. Framerates for large CG plugins (e.g., in-window Netflix streaming) should be higher.

Review URL: http://codereview.chromium.org/1629017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44490 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 21 insertions, 7 deletions

diff --git a/chrome/renderer/webplugin_delegate_proxy.cc b/chrome/renderer/webplugin_delegate_proxy.cc
index e11c848..5049bf4 100644
--- a/chrome/renderer/webplugin_delegate_proxy.cc
+++ b/chrome/renderer/webplugin_delegate_proxy.cc
@@ -533,6 +533,7 @@ void WebPluginDelegateProxy::UpdateGeometry(const gfx::Rect& window_rect,
   param.clip_rect = clip_rect;
   param.windowless_buffer = TransportDIB::DefaultHandleValue();
   param.background_buffer = TransportDIB::DefaultHandleValue();
+  param.transparent = transparent_;
 
 #if defined(OS_POSIX)
   // If we're using POSIX mmap'd TransportDIBs, sending the handle across
@@ -1241,15 +1242,28 @@ void WebPluginDelegateProxy::CopyFromTransportToBacking(const gfx::Rect& rect) {
   }
 
   // Copy the damaged rect from the transport bitmap to the backing store.
-  gfx::Rect dest_rect = rect;
 #if defined(OS_MACOSX)
-  FlipRectVerticallyWithHeight(&dest_rect, plugin_rect_.height());
-  gfx::NativeDrawingContext backing_context =
-      backing_store_canvas_.get()->getTopPlatformDevice().GetBitmapContext();
-  CGContextClearRect(backing_context, dest_rect.ToCGRect());
-#endif
-  BlitCanvasToCanvas(backing_store_canvas_.get(), dest_rect,
+  // Blitting the bits directly is much faster than going through CG, and since
+  // since the goal is just to move the raw pixels between two bitmaps with the
+  // same pixel format (no compositing, color correction, etc.), it's safe.
+  const size_t stride =
+      skia::PlatformCanvas::StrideForWidth(plugin_rect_.width());
+  const size_t chunk_size = 4 * rect.width();
+  char* source_data = static_cast<char*>(transport_store_->memory()) +
+      rect.y() * stride + 4 * rect.x();
+  // The two bitmaps are flipped relative to each other.
+  int dest_starting_row = plugin_rect_.height() - rect.y() - 1;
+  char* target_data = static_cast<char*>(backing_store_->memory()) +
+      dest_starting_row * stride + 4 * rect.x();
+  for (int row = 0; row < rect.height(); ++row) {
+    memcpy(target_data, source_data, chunk_size);
+    source_data += stride;
+    target_data -= stride;
+  }
+#else
+  BlitCanvasToCanvas(backing_store_canvas_.get(), rect,
                      transport_store_canvas_.get(), rect.origin());
+#endif
   backing_store_painted_ = backing_store_painted_.Union(rect);
 }