Fix offscren invalidation in windowless plugins

Fixes two related issues:
- An invalidate that was entirely off screen, but for a plugin that was partial on-screen, would not trigger a paint when the damaged area was scrolled back into view (all platforms).
- When a Mac plugin's container became visible, damaged regions were not repainted (Mac only).

BUG=41383
TEST=See bug.

Review URL: http://codereview.chromium.org/1629018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44582 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 10 insertions, 3 deletions

diff --git a/chrome/plugin/webplugin_proxy.cc b/chrome/plugin/webplugin_proxy.cc
index 2dfc7a2..c3654e8 100644
--- a/chrome/plugin/webplugin_proxy.cc
+++ b/chrome/plugin/webplugin_proxy.cc
@@ -130,8 +130,8 @@ void WebPluginProxy::InvalidateRect(const gfx::Rect& rect) {
   // This is not true because scrolling (or window resize) could occur and be
   // handled by the renderer before it receives the InvalidateRect message,
   // changing the clip rect and then not painting.
-  if (invalidate_rect.IsEmpty() ||
-      !delegate_->GetClipRect().Intersects(invalidate_rect))
+  if (damaged_rect_.IsEmpty() ||
+      !delegate_->GetClipRect().Intersects(damaged_rect_))
     return;
 
   // Only send a single InvalidateRect message at a time.  From DidPaint we
@@ -457,7 +457,7 @@ void WebPluginProxy::UpdateGeometry(
   // Send over any pending invalidates which occured when the plugin was
   // off screen.
   if (delegate_->IsWindowless() && !clip_rect.IsEmpty() &&
-      old_clip_rect.IsEmpty() && !damaged_rect_.IsEmpty()) {
+      !damaged_rect_.IsEmpty()) {
     InvalidateRect(damaged_rect_);
   }
 
diff --git a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
index 7f33a52..a2ee61d 100644
--- a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
+++ b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
@@ -688,6 +688,13 @@ void WebPluginDelegateImpl::SetContainerVisibility(bool is_visible) {
     PluginVisibilityChanged();
     WindowlessSetWindow(true);
   }
+
+  // When the plugin become visible, send an empty invalidate. If there were any
+  // pending invalidations this will trigger a paint event for the damaged
+  // region, and if not it's a no-op. This is necessary since higher levels
+  // that would normally do this weren't responsible for the clip_rect_ change).
+  if (!clip_rect_.IsEmpty())
+    instance()->webplugin()->InvalidateRect(gfx::Rect());
 }
 
 // Update the size of the IOSurface to match the current size of the plug-in,