Updated OSX to blacklist multisampling when multiple monitors are connected

content/browser/gpu/gpu_data_manager_impl.cc

Index: content/browser/gpu/gpu_data_manager_impl.cc
diff --git a/content/browser/gpu/gpu_data_manager_impl.cc b/content/browser/gpu/gpu_data_manager_impl.cc
index 1ac0c173c13c6c67c79d3c52fd42ac25e2fe51f5..3d1083c886c92b7961dd808d4bafbec39a95ef1e 100644
--- a/content/browser/gpu/gpu_data_manager_impl.cc
+++ b/content/browser/gpu/gpu_data_manager_impl.cc
@@ -78,12 +78,25 @@ std::string IntSetToString(const std::set<int>& list) {
 void DisplayReconfigCallback(CGDirectDisplayID display,
                              CGDisplayChangeSummaryFlags flags,
                              void* gpu_data_manager) {
-  if (flags & kCGDisplayAddFlag) {
-    GpuDataManagerImpl* manager =
-        reinterpret_cast<GpuDataManagerImpl*>(gpu_data_manager);
-    DCHECK(manager);
-    manager->HandleGpuSwitch();
+  if(flags == kCGDisplayBeginConfigurationFlag)
+    return; // This call contains no information about the display change
+
+  GpuDataManagerImpl* manager =
+      reinterpret_cast<GpuDataManagerImpl*>(gpu_data_manager);
+  DCHECK(manager);
+
+  uint32_t displayCount;
+  CGGetActiveDisplayList(0, NULL, &displayCount);
+
+  bool fireGpuSwitch = flags & kCGDisplayAddFlag;
+
+  if (displayCount != manager->display_count_) {
+    manager->display_count_ = displayCount;
+    fireGpuSwitch = true;
   }
+
+  if (fireGpuSwitch)
+    manager->HandleGpuSwitch();
 }
 #endif  // OS_MACOSX
 
@@ -130,6 +143,14 @@ bool GpuDataManagerImpl::IsFeatureBlacklisted(int feature) const {
     return false;
   }
 
+#if defined(OS_MACOSX)
+  // Many Mac laptops have buggy behavior when rendering to fullscreen
+  // multisampled buffers on an external monitor.
+  if(display_count_ > 1 && feature == GPU_FEATURE_TYPE_MULTISAMPLING) {
+      return true;

[Ken Russell (switch to Gerrit), 2013/05/06 21:59:04]

I thought per our earlier discussion that this was going to be handled
differently -- that instead of blacklisting and unblacklisting the feature, that
GpuDataManagerImpl::UpdateRendererWebPrefs was going to be modified. That way
the change in src/gpu/command_buffer/service/feature_info.cc wouldn't be
necessary; that one is concerning.

+  }
+#endif
+
   return (blacklisted_features_.count(feature) == 1);
 }
 
@@ -712,6 +733,7 @@ GpuDataManagerImpl::GpuDataManagerImpl()
   }
 
 #if defined(OS_MACOSX)
+  CGGetActiveDisplayList (0, NULL, &display_count_);
   CGDisplayRegisterReconfigurationCallback(DisplayReconfigCallback, this);
 #endif  // OS_MACOSX
 }