[ios blink] Fix single process tests

Single process tests were failing because no
BELayerHierarchyTransport was registered. Since this
is all in process, just create a stub transport for
now.

Change-Id: I9c7146787648ccd9377b60f51283efe8ff590637
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6394815
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1437842}

content/gpu/in_process_gpu_thread.cc

@@ -25,6 +25,10 @@
 #include "base/android/jni_android.h"
 #endif
 
+#if BUILDFLAG(IS_IOS)
+#include "gpu/ipc/common/ios/be_layer_hierarchy_transport.h"
+#endif
+
 namespace content {
 namespace {
 
@@ -34,6 +38,25 @@ BASE_FEATURE(kInProcessGpuUseIOThread,
 
 }  // namespace
 
+#if BUILDFLAG(IS_IOS)
+class InProcessGpuThread::BELayerHierarchyTransportImpl
+    : public gpu::BELayerHierarchyTransport {
+ public:
+  BELayerHierarchyTransportImpl() {
+    gpu::BELayerHierarchyTransport::SetInstance(this);
+  }
+  ~BELayerHierarchyTransportImpl() override {
+    gpu::BELayerHierarchyTransport::SetInstance(nullptr);
+  }
+
+  void ForwardBELayerHierarchyToBrowser(
+      gpu::SurfaceHandle surface_handle,
+      xpc_object_t ipc_representation) override {
+    // Nothing to do.
+  }
+};
+#endif
+
 InProcessGpuThread::InProcessGpuThread(
     const InProcessChildThreadParams& params,
     const gpu::GpuPreferences& gpu_preferences)
@@ -65,6 +88,11 @@ void InProcessGpuThread::Init() {
   io_thread_type = base::ThreadType::kDisplayCritical;
 #endif
 
+#if BUILDFLAG(IS_IOS)
+  be_layer_transport_ =
+      std::make_unique<InProcessGpuThread::BELayerHierarchyTransportImpl>();
+#endif
+
   if (base::FeatureList::IsEnabled(kInProcessGpuUseIOThread)) {
     gpu_process_ = std::make_unique<ChildProcess>(params_.child_io_runner());
   } else {

content/gpu/in_process_gpu_thread.h

@@ -7,6 +7,7 @@
 
 #include "base/memory/raw_ptr.h"
 #include "base/threading/thread.h"
+#include "build/build_config.h"
 #include "content/common/content_export.h"
 #include "content/common/in_process_child_thread_params.h"
 #include "gpu/config/gpu_preferences.h"
@@ -32,11 +33,18 @@ class InProcessGpuThread : public base::Thread {
   void CleanUp() override;
 
  private:
+#if BUILDFLAG(IS_IOS)
+  class BELayerHierarchyTransportImpl;
+#endif
+
   InProcessChildThreadParams params_;
 
   // Deleted in CleanUp() on the gpu thread, so don't use smart pointers.
   std::unique_ptr<ChildProcess> gpu_process_;
   gpu::GpuPreferences gpu_preferences_;
+#if BUILDFLAG(IS_IOS)
+  std::unique_ptr<BELayerHierarchyTransportImpl> be_layer_transport_;
+#endif
 };
 
 CONTENT_EXPORT base::Thread* CreateInProcessGpuThread(