Revert of Pass initial size and GPU preference via context attributes

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 a43b39dd21d59a1de6dff1ddc1efd61596b5d7b4..1226bb4b64d5e759bbd6b7a79c9962e2c3cc194b 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -452,7 +452,8 @@
       std::move(gpu_channel_host), stream_id, stream_priority,
       gpu::kNullSurfaceHandle,
       GURL("chrome://gpu/RenderThreadImpl::CreateOffscreenContext"),
-      automatic_flushes, support_locking, limits, attributes, nullptr, type));
+      gl::PreferIntegratedGpu, automatic_flushes, support_locking, limits,
+      attributes, nullptr, type));
 }
 
 }  // namespace
@@ -1905,7 +1906,8 @@
       new ContextProviderCommandBuffer(
           gpu_channel_host, gpu::GPU_STREAM_DEFAULT,
           gpu::GpuStreamPriority::NORMAL, gpu::kNullSurfaceHandle, url,
-          automatic_flushes, support_locking, limits, attributes, share_context,
+          gl::PreferIntegratedGpu, automatic_flushes, support_locking, limits,
+          attributes, share_context,
           command_buffer_metrics::RENDER_COMPOSITOR_CONTEXT));
 
   if (layout_test_deps_) {