Re-land: cc: Implement shared worker contexts.

ui/compositor/test/in_process_context_provider.h

Index: ui/compositor/test/in_process_context_provider.h
diff --git a/ui/compositor/test/in_process_context_provider.h b/ui/compositor/test/in_process_context_provider.h
index 0f5f35f14123a1cebeb89f9ffd23b8d82424819d..628eaecf497c5bbfcb11a92c8606ee1106d16e6c 100644
--- a/ui/compositor/test/in_process_context_provider.h
+++ b/ui/compositor/test/in_process_context_provider.h
@@ -38,15 +38,6 @@ class InProcessContextProvider : public cc::ContextProvider {
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
       gpu::ImageFactory* image_factory);
 
- private:
-  InProcessContextProvider(
-      const gpu::gles2::ContextCreationAttribHelper& attribs,
-      gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
-      gpu::ImageFactory* image_factory,
-      gfx::AcceleratedWidget window,
-      const std::string& debug_name);
-  ~InProcessContextProvider() override;
-
   // cc::ContextProvider:
   bool BindToCurrentThread() override;
   void DetachFromThread() override;
@@ -66,6 +57,15 @@ class InProcessContextProvider : public cc::ContextProvider {
       const MemoryPolicyChangedCallback& memory_policy_changed_callback)
       override;
 
+ private:
+  InProcessContextProvider(
+      const gpu::gles2::ContextCreationAttribHelper& attribs,
+      gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
+      gpu::ImageFactory* image_factory,
+      gfx::AcceleratedWidget window,
+      const std::string& debug_name);
+  ~InProcessContextProvider() override;
+
   void OnLostContext();
 
   base::ThreadChecker main_thread_checker_;