Revert "[ios blink] Make webnn work on the device"

This reverts commit cd5897004c.

Reason for revert: https://ci.chromium.org/ui/p/chromium/builders/ci/mac14-arm64-rel-tests/23238/overview

Bug: 40254930
Original change's description:
> [ios blink] Make webnn work on the device
>
> tflite as a fallback works correctly on iOS in the GPU process.
> CoreML model requires file system access to compile a model
> and the GPU process is restricted from having file access. We've
> asked Apple to provide an update how CoreML can be used in the
> sandboxed rendering process.
>
> Bug: 40254930
> Change-Id: I72598db882db38fa43d5d04f4c6055cbafb33a87
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6543648
> Reviewed-by: Reilly Grant <reillyg@chromium.org>
> Reviewed-by: Joe Mason <joenotcharles@google.com>
> Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1460093}

Bug: 40254930
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I898a1e35dd74d9413cbdc2a88cef9214708fabab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6547278
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Owners-Override: Matt Reichhoff <mreichhoff@chromium.org>
Reviewed-by: Matt Reichhoff <mreichhoff@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1460154}

services/webnn/BUILD.gn

@@ -106,7 +106,7 @@ component("webnn_service") {
     libs = [ "dxgi.lib" ]
   }
 
-  if (is_apple) {
+  if (is_mac) {
     sources += [
       "coreml/buffer_content_coreml.h",
       "coreml/buffer_content_coreml.mm",

services/webnn/coreml/graph_impl_coreml.mm

@@ -29,7 +29,6 @@
 #include "base/task/bind_post_task.h"
 #include "base/task/thread_pool.h"
 #include "base/types/expected_macros.h"
-#include "build/build_config.h"
 #include "mojo/public/cpp/base/big_buffer.h"
 #include "mojo/public/cpp/bindings/self_owned_associated_receiver.h"
 #include "services/webnn/coreml/buffer_content_coreml.h"
@@ -80,7 +79,6 @@ namespace {
 // compilation process.
 struct ScopedModelPaths {
   ~ScopedModelPaths() {
-#if BUILDFLAG(IS_MAC)
     if (base::CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kWebNNCoreMlDumpModel)) {
       const auto dump_directory =
@@ -102,7 +100,6 @@ struct ScopedModelPaths {
         }
       }
     }
-#endif
     // Though the destructors of ScopedTempDir will delete these directories.
     // Explicitly delete them here to check for success.
     if (model_file_dir.IsValid()) {

services/webnn/features.gni

@@ -5,11 +5,9 @@
 import("//build/config/features.gni")
 import("//services/on_device_model/on_device_model.gni")
 
-assert(use_blink)
-
 declare_args() {
-  # TFLite is used as a fallback option on Apple and Windows.
-  webnn_use_tflite = is_android || is_chromeos || is_linux || is_apple || is_win
+  # TFLite is used as a fallback option on macOS and Windows.
+  webnn_use_tflite = is_android || is_chromeos || is_linux || is_mac || is_win
 
   # Enable the GPU delegate provided by the Optimization Guide library.
   webnn_use_chrome_ml_api = enable_ml_internal

services/webnn/public/mojom/features.mojom

@@ -18,19 +18,10 @@ feature kExperimentalWebMachineLearningNeuralNetwork {
 };
 
 // Enables the Core ML backend for WebNN.
-[EnableIf=is_apple]
+[EnableIf=is_mac]
 feature kWebNNCoreML {
   const string name = "WebNNCoreML";
-
-  // macOS default state is enabled.
-  [EnableIf=is_macos]
   const bool default_state = true;
-
-  // iOS default state is disabled since there are sandbox issues
-  // with using CoreML in the GPU process, we are waiting to hear back
-  // from Apple. https://crbug.com/417496826
-  [EnableIf=is_ios]
-  const bool default_state = false;
 };
 
 // Enables the DirectML backend for WebNN.

services/webnn/webnn_context_provider_impl.cc

@@ -24,9 +24,6 @@
 
 #if BUILDFLAG(IS_MAC)
 #include "base/mac/mac_util.h"
-#endif
-
-#if BUILDFLAG(IS_APPLE)
 #include "services/webnn/coreml/context_impl_coreml.h"
 #endif
 
@@ -190,18 +187,15 @@ void WebNNContextProviderImpl::CreateWebNNContext(
   }
 #endif  // BUILDFLAG(IS_WIN)
 
-#if BUILDFLAG(IS_APPLE)
-  if (__builtin_available(macOS 14, *)) {
-    if (base::FeatureList::IsEnabled(mojom::features::kWebNNCoreML)
 #if BUILDFLAG(IS_MAC)
-        && base::mac::GetCPUType() == base::mac::CPUType::kArm
-#endif  // BUILDFLAG(IS_MAC)
-    ) {
+  if (__builtin_available(macOS 14, *)) {
+    if (base::FeatureList::IsEnabled(mojom::features::kWebNNCoreML) &&
+        base::mac::GetCPUType() == base::mac::CPUType::kArm) {
       context_impl = std::make_unique<coreml::ContextImplCoreml>(
           std::move(receiver), this, std::move(options));
     }
   }
-#endif  // BUILDFLAG(IS_APPLE)
+#endif  // BUILDFLAG(IS_MAC)
 
 #if BUILDFLAG(WEBNN_USE_TFLITE)
   if (!context_impl) {