Revert of cc: Implement shared worker contexts.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 8c0cad2936c44528ff14a011227246d059c3f6b4..ab04ccd011977e9b192aa833e15b41e2a3f60085 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -845,7 +845,6 @@
   main_thread_compositor_task_runner_ = NULL;
 
   // Context providers must be released prior to destroying the GPU channel.
-  shared_worker_context_provider_ = nullptr;
   gpu_va_context_provider_ = nullptr;
   shared_main_thread_contexts_ = nullptr;
 
@@ -1891,31 +1890,6 @@
   return raster_worker_pool_.get();
 }
 
-scoped_refptr<ContextProviderCommandBuffer>
-RenderThreadImpl::SharedWorkerContextProvider() {
-  DCHECK(IsMainThread());
-  // Try to reuse existing shared worker context provider.
-  bool shared_worker_context_provider_lost = false;
-  if (shared_worker_context_provider_) {
-    // Note: If context is lost, delete reference after releasing the lock.
-    base::AutoLock lock(*shared_worker_context_provider_->GetLock());
-    if (shared_worker_context_provider_->ContextGL()
-            ->GetGraphicsResetStatusKHR() != GL_NO_ERROR) {
-      shared_worker_context_provider_lost = true;
-    }
-  }
-  if (!shared_worker_context_provider_ || shared_worker_context_provider_lost) {
-    shared_worker_context_provider_ = ContextProviderCommandBuffer::Create(
-        CreateOffscreenContext3d(), RENDER_WORKER_CONTEXT);
-    if (shared_worker_context_provider_ &&
-        !shared_worker_context_provider_->BindToCurrentThread())
-      shared_worker_context_provider_ = nullptr;
-    if (shared_worker_context_provider_)
-      shared_worker_context_provider_->SetupLock();
-  }
-  return shared_worker_context_provider_;
-}
-
 void RenderThreadImpl::SampleGamepads(blink::WebGamepads* data) {
   blink_platform_impl_->sampleGamepads(*data);
 }