Disable threaded compositing when texture sharing is blacklisted

content/browser/gpu/compositor_util.cc

Index: content/browser/gpu/compositor_util.cc
diff --git a/content/browser/gpu/compositor_util.cc b/content/browser/gpu/compositor_util.cc
index d95459071877d1f8dffa3257239c22629e145f81..bef0a97fcc9ce72a32bb11b975e8204198486a73 100644
--- a/content/browser/gpu/compositor_util.cc
+++ b/content/browser/gpu/compositor_util.cc
@@ -47,6 +47,15 @@ bool IsThreadedCompositingEnabled() {
   if (!CanDoAcceleratedCompositing())
     return false;
 
+  const GpuDataManager* gpu_data_manager = GpuDataManager::GetInstance();
+  GpuFeatureType blacklisted_features =
+      gpu_data_manager->GetBlacklistedFeatures();
+  // Disallow threaded compositing when texture sharing is blacklisted since
+  // this triggers renderer-side readbacks for the thumbnailer / extensions.
+  // http://crbug.com/158747
+  if (blacklisted_features & GPU_FEATURE_TYPE_TEXTURE_SHARING)
+    return false;
+
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   // Command line switches take precedence over field trials.