gpu: Introduce GpuChannelEstablishFactory.

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index 8a60ed12838d8017107585a330d04eb7f0458f8f..77d9f84fcb36d1093c2d7f7f9c0e90e0b7dc907d 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -303,33 +303,30 @@ void GpuProcessTransportFactory::CreateOutputSurface(
 #endif
 
   const bool use_vulkan = static_cast<bool>(SharedVulkanContextProvider());
-  const bool use_mus = IsUsingMus();
   const bool create_gpu_output_surface =
       ShouldCreateGpuOutputSurface(compositor.get());
   if (create_gpu_output_surface && !use_vulkan) {
-    base::Closure callback(
+    gpu::GpuChannelEstablishedCallback callback(
         base::Bind(&GpuProcessTransportFactory::EstablishedGpuChannel,
                    callback_factory_.GetWeakPtr(), compositor,
                    create_gpu_output_surface, 0));
-    if (!use_mus) {
+    auto* factory = gpu::GpuChannelEstablishFactory::GetInstance();
+    if (factory) {
+      factory->EstablishGpuChannel(callback);
+    } else {
       BrowserGpuChannelHostFactory::instance()->EstablishGpuChannel(
           CAUSE_FOR_GPU_LAUNCH_SHARED_WORKER_THREAD_CONTEXT, callback);
-    } else {
-#if defined(MOJO_RUNNER_CLIENT)
-      ui::GpuService::GetInstance()->EstablishGpuChannel(callback);
-#else
-      NOTREACHED();
-#endif
     }
   } else {
-    EstablishedGpuChannel(compositor, create_gpu_output_surface, 0);
+    EstablishedGpuChannel(compositor, create_gpu_output_surface, 0, nullptr);
   }
 }
 
 void GpuProcessTransportFactory::EstablishedGpuChannel(
     base::WeakPtr<ui::Compositor> compositor,
     bool create_gpu_output_surface,
-    int num_attempts) {
+    int num_attempts,
+    scoped_refptr<gpu::GpuChannelHost> established_channel_host) {
   if (!compositor)
     return;
 
@@ -357,7 +354,6 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
 
   scoped_refptr<cc::VulkanInProcessContextProvider> vulkan_context_provider =
       SharedVulkanContextProvider();
-  const bool use_mus = IsUsingMus();
   scoped_refptr<ContextProviderCommandBuffer> context_provider;
   if (create_gpu_output_surface && !vulkan_context_provider) {
     // Try to reuse existing worker context provider.
@@ -375,20 +371,8 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
     }
 
     scoped_refptr<gpu::GpuChannelHost> gpu_channel_host;
-    if (GpuDataManagerImpl::GetInstance()->CanUseGpuBrowserCompositor()) {
-      // We attempted to do EstablishGpuChannel already, so we just use
-      // GetGpuChannel() instead of EstablishGpuChannelSync().
-      if (!use_mus) {
-        gpu_channel_host =
-            BrowserGpuChannelHostFactory::instance()->GetGpuChannel();
-      } else {
-#if defined(MOJO_RUNNER_CLIENT)
-        gpu_channel_host = ui::GpuService::GetInstance()->GetGpuChannel();
-#else
-        NOTREACHED();
-#endif
-      }
-    }
+    if (GpuDataManagerImpl::GetInstance()->CanUseGpuBrowserCompositor())
+      gpu_channel_host = std::move(established_channel_host);
 
     if (!gpu_channel_host) {
       shared_worker_context_provider_ = nullptr;
@@ -453,19 +437,17 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
 
     if (!created_gpu_browser_compositor) {
       // Try again.
-      base::Closure callback(
+      gpu::GpuChannelEstablishedCallback callback(
           base::Bind(&GpuProcessTransportFactory::EstablishedGpuChannel,
                      callback_factory_.GetWeakPtr(), compositor,
                      create_gpu_output_surface, num_attempts + 1));
-      if (!use_mus) {
+      auto* factory = gpu::GpuChannelEstablishFactory::GetInstance();
+      if (factory) {
+        DCHECK(IsUsingMus());
+        factory->EstablishGpuChannel(callback);
+      } else {
         BrowserGpuChannelHostFactory::instance()->EstablishGpuChannel(
             CAUSE_FOR_GPU_LAUNCH_SHARED_WORKER_THREAD_CONTEXT, callback);
-      } else {
-#if defined(MOJO_RUNNER_CLIENT)
-        ui::GpuService::GetInstance()->EstablishGpuChannel(callback);
-#else
-        NOTREACHED();
-#endif
       }
       return;
     }
@@ -533,6 +515,7 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
       } else {
         std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>
             validator;
+        const bool use_mus = IsUsingMus();
 #if !defined(OS_MACOSX)
         // Overlays are only supported on surfaceless output surfaces on Mac.
         if (!use_mus)
@@ -797,18 +780,14 @@ GpuProcessTransportFactory::SharedMainThreadContextProvider() {
   if (!GpuDataManagerImpl::GetInstance()->CanUseGpuBrowserCompositor())
     return nullptr;
 
-  const bool use_mus = IsUsingMus();
   scoped_refptr<gpu::GpuChannelHost> gpu_channel_host;
-  if (!use_mus) {
+  auto* factory = gpu::GpuChannelEstablishFactory::GetInstance();
+  if (factory) {
+    gpu_channel_host = factory->EstablishGpuChannelSync();
+  } else {
     gpu_channel_host =
         BrowserGpuChannelHostFactory::instance()->EstablishGpuChannelSync(
             CAUSE_FOR_GPU_LAUNCH_BROWSER_SHARED_MAIN_THREAD_CONTEXT);
-  } else {
-#if defined(MOJO_RUNNER_CLIENT)
-    gpu_channel_host = ui::GpuService::GetInstance()->EstablishGpuChannelSync();
-#else
-    NOTREACHED();
-#endif
   }
 
   if (!gpu_channel_host)