mac: Remove code to support OS X 10.10 in //components/metal_util

Bug: 1153883
Change-Id: Ieb2ee69ba93e0469cbe307dfb1f12687a0a1a702
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572379
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833778}

components/metal_util/device.mm

@@ -12,7 +12,6 @@
 namespace metal {
 
 MTLDevicePtr CreateDefaultDevice() {
-  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());
@@ -30,10 +29,6 @@ MTLDevicePtr CreateDefaultDevice() {
     return nullptr;
   }
   return device_to_use.release();
-  }
-  // If no device was found, or if the macOS version is too old for Metal,
-  // return no context provider.
-  return nullptr;
 }
 
 }  // namespace metal

components/metal_util/test_shader.mm

@@ -697,8 +697,7 @@ base::ScopedDispatchObject<dispatch_data_t> GetLibraryData() {
 }
 
 // State shared between the compiler callback and the caller.
-class API_AVAILABLE(macos(10.11)) TestShaderState
-    : public base::RefCountedThreadSafe<TestShaderState> {
+class TestShaderState : public base::RefCountedThreadSafe<TestShaderState> {
  public:
   TestShaderState(TestShaderCallback callback,
                   TestShaderComponent component,