GpuService: introduce GetGpuMemoryBufferAttribs as a mojo interface

services/ui/gpu/gpu_service.cc

Index: services/ui/gpu/gpu_service.cc
diff --git a/services/ui/gpu/gpu_service.cc b/services/ui/gpu/gpu_service.cc
index 03c8823b173a4a67a5d29dfcc68e03b1f5a9d8e0..d0a2059365743da0c82eb299cf5fb2e216a8209f 100644
--- a/services/ui/gpu/gpu_service.cc
+++ b/services/ui/gpu/gpu_service.cc
@@ -241,6 +241,33 @@ void GpuService::DestroyGpuMemoryBuffer(gfx::GpuMemoryBufferId id,
   gpu_channel_manager_->DestroyGpuMemoryBuffer(id, client_id, sync_token);
 }
 
+void GpuService::GetGpuMemoryBufferAttribs(
+    const GetGpuMemoryBufferAttribsCallback& callback) {
+  gfx::GpuMemoryBufferAttribVector supported_attribs;
+
+  for (int i = 0; i < static_cast<int>(gfx::BufferUsage::LAST); i++) {
+    gfx::GpuMemoryBufferAttribVector tmp =
+        gpu_memory_buffer_factory_->GetSupportedGpuMemoryBufferAttribsForUsage(
+            static_cast<gfx::BufferUsage>(i));
+    if (tmp.size() == 0)
+      continue;
+
+    gfx::GpuMemoryBufferAttribVector intersection;
+    std::sort(tmp.begin(), tmp.end());
+
+    if (supported_attribs.size() == 0)
+      supported_attribs = std::move(tmp);
+    else {
+      std::set_intersection(supported_attribs.begin(), supported_attribs.end(),
+                            tmp.begin(), tmp.end(),
+                            std::back_inserter(intersection));
+      supported_attribs = std::move(intersection);
+    }
+  }
+
+  callback.Run(supported_attribs);

[sadrul, 2017/04/19 21:40:23]

Do we expect this list to change between requests? If not, can we cache it
during the first call, so that we don't have to do the work again for subsequent
calls?

[varad, 2017/04/21 13:01:32]

Done.

+}
+
 void GpuService::GetVideoMemoryUsageStats(
     const GetVideoMemoryUsageStatsCallback& callback) {
   if (io_runner_->BelongsToCurrentThread()) {