Fix a crash when scrolling a fast-path QuickDraw plugin

Two changes
- Only throw away QuickDraw plugin GWorlds when the size changes, so we don't get into this case in the first place
- Add a safety check so that if anything else like this happens, it will call SetWindow instead of crashing.

BUG=43007
TEST=Scroll a page with a QuickTime movie on 10.5; it shouldn't crash.

Review URL: http://codereview.chromium.org/1937004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46351 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 22 insertions, 7 deletions

diff --git a/webkit/glue/plugins/quickdraw_drawing_manager_mac.cc b/webkit/glue/plugins/quickdraw_drawing_manager_mac.cc
index 185d4db..424cc1e 100644
--- a/webkit/glue/plugins/quickdraw_drawing_manager_mac.cc
+++ b/webkit/glue/plugins/quickdraw_drawing_manager_mac.cc
@@ -41,11 +41,13 @@ void QuickDrawDrawingManager::SetFastPathEnabled(bool enabled) {
 void QuickDrawDrawingManager::SetTargetContext(CGContextRef context,
                                                const gfx::Size& plugin_size) {
   target_context_ = context;
-  plugin_size_ = plugin_size;
-  // Pitch the old GWorlds, since they are the wrong size now.
-  DestroyGWorlds();
-  if (fast_path_enabled_)
-    UpdateGWorlds();
+  if (plugin_size != plugin_size_) {
+    plugin_size_ = plugin_size;
+    // Pitch the old GWorlds, since they are the wrong size now.
+    DestroyGWorlds();
+    if (fast_path_enabled_)
+      UpdateGWorlds();
+  }
 }
 
 void QuickDrawDrawingManager::SetPluginWindow(WindowRef window) {
@@ -103,6 +105,8 @@ void QuickDrawDrawingManager::UpdateGWorlds() {
   // directly into the shared memory.
   NewGWorld(&plugin_world_, k32ARGBPixelFormat, &window_bounds,
             NULL, NULL, kNativeEndianPixMap);
+  if (fast_path_enabled_)
+    current_port_ = plugin_world_;
 }
 
 void QuickDrawDrawingManager::ScrapeWindow(WindowRef window,
diff --git a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
index c61ed22..c5ec61d 100644
--- a/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
+++ b/webkit/glue/plugins/webplugin_delegate_impl_mac.mm
@@ -660,7 +660,18 @@ void WebPluginDelegateImpl::WindowlessUpdateGeometry(
   bool clip_rect_changed = (clip_rect_ != old_clip_rect);
   bool window_size_changed = (window_rect.size() != window_rect_.size());
 
-  if (window_rect == window_rect_ && !clip_rect_changed)
+  bool force_set_window = false;
+#ifndef NP_NO_QUICKDRAW
+  // In a QuickDraw plugin, a geometry update might have caused a port change;
+  // if so, we need to call SetWindow even if nothing else changed.
+  if (qd_manager_.get() && (qd_port_.port != qd_manager_->port())) {
+    LOG(ERROR) << "Saving the day";
+    qd_port_.port = qd_manager_->port();
+    force_set_window = true;
+  }
+#endif
+
+  if (window_rect == window_rect_ && !clip_rect_changed && !force_set_window)
     return;
 
   if (old_clip_rect.IsEmpty() != clip_rect_.IsEmpty()) {
@@ -679,7 +690,7 @@ void WebPluginDelegateImpl::WindowlessUpdateGeometry(
   }
 #endif
 
-  if (window_size_changed || clip_rect_changed)
+  if (window_size_changed || clip_rect_changed || force_set_window)
     WindowlessSetWindow();
 }