Upstream various ios/web utilities and helpers

ios/web/web_view_util.mm

 // Copyright 2014 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 "ios/web/web_view_util.h"
 
+#include <Foundation/Foundation.h>
+#include <sys/sysctl.h>
+
 #include "base/ios/ios_util.h"
 
-namespace {
-
-// If true, UIWebView is always used even if WKWebView is available.
-bool g_force_ui_web_view = false;
-
-}  // namespace
-
 namespace web {
 
-bool IsWKWebViewEnabled() {
-#if defined(ENABLE_WKWEBVIEW)
-  // Eventually this may be a dynamic flag, but for now it's purely a
-  // compile-time option.
-  return !g_force_ui_web_view && base::ios::IsRunningOnIOS8OrLater();
+bool IsWKWebViewSupported() {
+  // WKWebView is available starting from iOS8.
+  if (!base::ios::IsRunningOnIOS8OrLater())
+    return false;
+
+// WKWebView does not work with 32-bit binaries running on 64-bit hardware.
+// (rdar://18268087)
+#if !defined(__LP64__)
+  NSString* simulator_model_id =
+      [[NSProcessInfo processInfo] environment][@"SIMULATOR_MODEL_IDENTIFIER"];
+  // For simulator it's not possible to query hw.cpu64bit_capable value as the
+  // function will return information for mac hardware rather than simulator.
+  if (simulator_model_id) {
+    // A set of known 32-bit simulators that are also iOS 8 compatible.
+    // (taken from iOS 8.1 SDK simulators list).
+    NSSet* known_32_bit_devices = [NSSet
+        setWithArray:@[ @"iPad2,1", @"iPad3,1", @"iPhone4,1", @"iPhone5,1" ]];
+    return [known_32_bit_devices containsObject:simulator_model_id];
+  }
+  uint32_t cpu64bit_capable = 0;
+  size_t sizes = sizeof(cpu64bit_capable);
+  sysctlbyname("hw.cpu64bit_capable", &cpu64bit_capable, &sizes, NULL, 0);
+  return !cpu64bit_capable;
 #else
-  return false;
+  return true;
 #endif
 }
 
-void SetForceUIWebView(bool flag) {
-  g_force_ui_web_view = flag;
-}
-
-bool GetForceUIWebView() {
-  return g_force_ui_web_view;
-}
-
 }  // namespace web