Skia/Metal raster: Add viz::MetalContextProvider

Add viz::MetalContextProvider, and add Metal to the Skia build by
default. Do not wire up any of this yet.

Bug: 952063
Change-Id: I897d052bdbf046114c1ddc0527c1d3cafc8777c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1577296Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652899}

components/viz/common/BUILD.gn

@@ -40,6 +40,34 @@ viz_component("resource_format_utils") {
   ]
 }
 
+if (is_mac) {
+  viz_component("metal_context_provider") {
+    output_name = "viz_metal_context_provider"
+
+    defines = [ "VIZ_METAL_CONTEXT_PROVIDER_IMPLEMENTATION" ]
+
+    sources = [
+      "gpu/metal_context_provider.h",
+      "gpu/metal_context_provider.mm",
+      "viz_metal_context_provider_export.h",
+    ]
+
+    public_deps = [
+      "//skia",
+    ]
+
+    deps = [
+      "//base",
+      "//ui/gfx",
+    ]
+
+    libs = [
+      "Metal.framework",
+      "Foundation.framework",
+    ]
+  }
+}
+
 if (enable_vulkan) {
   viz_component("vulkan_context_provider") {
     output_name = "viz_vulkan_context_provider"
@@ -256,6 +284,9 @@ viz_component("common") {
   if (enable_vulkan) {
     public_deps += [ ":vulkan_context_provider" ]
   }
+  if (is_mac) {
+    public_deps += [ ":metal_context_provider" ]
+  }
 }
 
 viz_source_set("unit_tests") {

components/viz/common/gpu/metal_context_provider.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_VIZ_COMMON_GPU_METAL_CONTEXT_PROVIDER_H_
+#define COMPONENTS_VIZ_COMMON_GPU_METAL_CONTEXT_PROVIDER_H_
+
+#include <memory>
+#include "components/viz/common/viz_metal_context_provider_export.h"
+
+class GrContext;
+
+namespace viz {
+
+// The MetalContextProvider provides a Metal-backed GrContext.
+class VIZ_METAL_CONTEXT_PROVIDER_EXPORT MetalContextProvider {
+ public:
+  // Create and return a MetalContextProvider if possible. May return nullptr
+  // if no Metal devices exist.
+  static std::unique_ptr<MetalContextProvider> Create();
+  virtual ~MetalContextProvider() {}
+
+  virtual GrContext* GetGrContext() = 0;
+  virtual void* GetMTLDevice() = 0;
+};
+
+}  // namespace viz
+
+#endif  // COMPONENTS_VIZ_COMMON_GPU_METAL_CONTEXT_PROVIDER_H_

components/viz/common/gpu/metal_context_provider.mm

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/viz/common/gpu/metal_context_provider.h"
+
+#include "base/mac/scoped_nsobject.h"
+#include "third_party/skia/include/gpu/GrContext.h"
+
+#import <Metal/Metal.h>
+
+namespace viz {
+
+namespace {
+
+struct API_AVAILABLE(macos(10.11)) MetalContextProviderImpl
+    : public MetalContextProvider {
+ public:
+  explicit MetalContextProviderImpl(
+      base::scoped_nsprotocol<id<MTLDevice>> device)
+      : device_(device) {
+    command_queue_.reset([device_ newCommandQueue]);
+    // GrContext::MakeMetal will take ownership of the objects passed in. Retain
+    // the objects before passing them to MakeMetal so that the objects in
+    // |this| are also valid.
+    gr_context_ =
+        GrContext::MakeMetal([device_ retain], [command_queue_ retain]);
+    DCHECK(gr_context_);
+  }
+  ~MetalContextProviderImpl() override {}
+  GrContext* GetGrContext() override { return gr_context_.get(); }
+  void* GetMTLDevice() override { return device_.get(); }
+
+ private:
+  base::scoped_nsprotocol<id<MTLDevice>> device_;
+  base::scoped_nsprotocol<id<MTLCommandQueue>> command_queue_;
+  sk_sp<GrContext> gr_context_;
+};
+
+}  // namespace
+
+// static
+std::unique_ptr<MetalContextProvider> MetalContextProvider::Create() {
+  if (@available(macOS 10.11, *)) {
+    // First attempt to find a low power device to use.
+    base::scoped_nsprotocol<id<MTLDevice>> device_to_use;
+    base::scoped_nsobject<NSArray<id<MTLDevice>>> devices(MTLCopyAllDevices());
+    for (id<MTLDevice> device in devices.get()) {
+      if ([device isLowPower]) {
+        device_to_use.reset(device, base::scoped_policy::RETAIN);
+        break;
+      }
+    }
+    // Failing that, use the system default device.
+    if (!device_to_use)
+      device_to_use.reset(MTLCreateSystemDefaultDevice());
+    if (device_to_use)
+      return std::make_unique<MetalContextProviderImpl>(device_to_use);
+  }
+  // If no device was found, or if the macOS version is too old for Metal,
+  // return no context provider.
+  return nullptr;
+}
+
+}  // namespace viz

components/viz/common/viz_metal_context_provider_export.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_VIZ_COMMON_VIZ_METAL_CONTEXT_PROVIDER_EXPORT_H_
+#define COMPONENTS_VIZ_COMMON_VIZ_METAL_CONTEXT_PROVIDER_EXPORT_H_
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(VIZ_METAL_CONTEXT_PROVIDER_IMPLEMENTATION)
+#define VIZ_METAL_CONTEXT_PROVIDER_EXPORT __declspec(dllexport)
+#else
+#define VIZ_METAL_CONTEXT_PROVIDER_EXPORT __declspec(dllimport)
+#endif  // defined(VIZ_METAL_CONTEXT_PROVIDER_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(VIZ_METAL_CONTEXT_PROVIDER_IMPLEMENTATION)
+#define VIZ_METAL_CONTEXT_PROVIDER_EXPORT __attribute__((visibility("default")))
+#else
+#define VIZ_METAL_CONTEXT_PROVIDER_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define VIZ_METAL_CONTEXT_PROVIDER_EXPORT
+#endif
+
+#endif  // COMPONENTS_VIZ_COMMON_VIZ_METAL_CONTEXT_PROVIDER_EXPORT_H_

skia/BUILD.gn

@@ -25,7 +25,6 @@ skia_support_skottie = true
 
 declare_args() {
   skia_whitelist_serialized_typefaces = false
-  skia_use_metal = false
 }
 
 # External-facing config for dependent code.
@@ -102,7 +101,10 @@ config("skia_config") {
   }
 
   if (is_mac) {
-    defines += [ "SK_BUILD_FOR_MAC" ]
+    defines += [
+      "SK_BUILD_FOR_MAC",
+      "SK_METAL",
+    ]
   }
 
   if (is_win) {
@@ -556,20 +558,14 @@ component("skia") {
   }
 
   if (is_mac) {
-    if (skia_use_metal) {
-      deps += [ ":skia_metal" ]
-      defines += [ "SK_METAL" ]
-      libs += [
-        "Metal.framework",
-        "Foundation.framework",
-      ]
-    }
-
+    deps += [ ":skia_metal" ]
+    defines += [ "SK_METAL" ]
     libs = [
       "AppKit.framework",
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
+      "Metal.framework",
       "Foundation.framework",
     ]
   }
@@ -801,7 +797,7 @@ skia_source_set("skia_opts") {
 }
 
 # Split out metal sources, because they require ARC.
-if (is_mac && skia_use_metal) {
+if (is_mac) {
   skia_source_set("skia_metal") {
     defines = [ "SK_METAL" ]
     sources = skia_metal_sources