mac: Load the system hotkeys after launch. (reland)

---------------Reland CL Description---------------------------
System mouse hotkeys were incorrectly being parsed as system keyboard hotkeys.

Other minor changes include:
- Expanded unit tests to include a sparsely populated symbolichotkeys.plist
from a real machine.
- Use correct types for the key_code and modifiers of the event.
- An event must have at least one of ctr/alt/cmd down to be considered a
hotkey.
- Use the NSDeviceIndependentModifierFlagsMask mask to prune out
device-dependent modifier flags, including event coalescing information.

---------------Original CL Description---------------------------
Original CL: https://codereview.chromium.org/370293004/

Shortly after launch, the system hotkeys are loaded and parsed. If a hotkey is
reserved by the system, it is not passed to the renderer. This allows system
hotkeys like (cmd + `) to work even if a flash plugin is selected.

Add a histogram to ensure that the system hotkey plist is being correctly
loaded and parsed.

BUG=383558, 395187
TEST=Open 2 Chrome windows. Navigate one to www.twitch.tv. The site should
include a flash plugin that automatically starts playing a video. Select the
flash plugin. The hotkey combination (cmd + `) should switch between the open
windows. The hotkey combination (cmd + L) should have no effect (it is a Chrome
hotkey, not a browser hotkey).

Review URL: https://codereview.chromium.org/408973002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@286737 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 1596 insertions, 0 deletions

diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 6b5cdd4..ce7e224 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -86,6 +86,7 @@
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 #include "content/browser/bootstrap_sandbox_mac.h"
+#include "content/browser/cocoa/system_hotkey_helper_mac.h"
 #include "content/browser/theme_helper_mac.h"
 #endif
 
@@ -1048,6 +1049,7 @@ int BrowserMainLoop::BrowserThreadsStarted() {
 
 #if defined(OS_MACOSX)
   ThemeHelperMac::GetInstance();
+  SystemHotkeyHelperMac::GetInstance()->DeferredLoadSystemHotkeys();
   if (ShouldEnableBootstrapSandbox()) {
     TRACE_EVENT0("startup",
         "BrowserMainLoop::BrowserThreadsStarted:BootstrapSandbox");
diff --git a/content/browser/cocoa/system_hotkey_helper_mac.h b/content/browser/cocoa/system_hotkey_helper_mac.h
new file mode 100644
index 0000000..63d9e51
--- /dev/null
+++ b/content/browser/cocoa/system_hotkey_helper_mac.h
@@ -0,0 +1,56 @@
+// 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.
+
+#ifndef CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_
+#define CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_
+
+#include "base/memory/singleton.h"
+#include "base/memory/weak_ptr.h"
+
+#ifdef __OBJC__
+@class NSDictionary;
+#else
+class NSDictionary;
+#endif
+
+namespace content {
+
+class SystemHotkeyMap;
+
+// This singleton holds a global mapping of hotkeys reserved by OSX.
+class SystemHotkeyHelperMac {
+ public:
+  // Return pointer to the singleton instance for the current process.
+  static SystemHotkeyHelperMac* GetInstance();
+
+  // Loads the system hot keys after a brief delay, to reduce file system access
+  // immediately after launch.
+  void DeferredLoadSystemHotkeys();
+
+  // Guaranteed to not be NULL.
+  SystemHotkeyMap* map() { return map_.get(); }
+
+ private:
+  friend struct DefaultSingletonTraits<SystemHotkeyHelperMac>;
+
+  SystemHotkeyHelperMac();
+  ~SystemHotkeyHelperMac();
+
+  // Must be called from the FILE thread. Loads the file containing the system
+  // hotkeys into a NSDictionary* object, and passes the result to FileDidLoad
+  // on the UI thread.
+  void LoadSystemHotkeys();
+
+  // Must be called from the UI thread.  This takes ownership of |dictionary|.
+  // Parses the system hotkeys from the plist stored in |dictionary|.
+  void FileDidLoad(NSDictionary* dictionary);
+
+  scoped_ptr<SystemHotkeyMap> map_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemHotkeyHelperMac);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_
diff --git a/content/browser/cocoa/system_hotkey_helper_mac.mm b/content/browser/cocoa/system_hotkey_helper_mac.mm
new file mode 100644
index 0000000..68c5282
--- /dev/null
+++ b/content/browser/cocoa/system_hotkey_helper_mac.mm
@@ -0,0 +1,77 @@
+// 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 "content/browser/cocoa/system_hotkey_helper_mac.h"
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/mac/foundation_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
+#include "content/browser/cocoa/system_hotkey_map.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+
+NSString* kSystemHotkeyPlistExtension =
+    @"/Preferences/com.apple.symbolichotkeys.plist";
+
+// Amount of time to delay loading the hotkeys in seconds.
+const int kLoadHotkeysDelaySeconds = 10;
+
+}  // namespace
+
+namespace content {
+
+// static
+SystemHotkeyHelperMac* SystemHotkeyHelperMac::GetInstance() {
+  return Singleton<SystemHotkeyHelperMac>::get();
+}
+
+void SystemHotkeyHelperMac::DeferredLoadSystemHotkeys() {
+  BrowserThread::PostDelayedTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&SystemHotkeyHelperMac::LoadSystemHotkeys,
+                 base::Unretained(this)),
+      base::TimeDelta::FromSeconds(kLoadHotkeysDelaySeconds));
+}
+
+SystemHotkeyHelperMac::SystemHotkeyHelperMac() : map_(new SystemHotkeyMap) {
+}
+
+SystemHotkeyHelperMac::~SystemHotkeyHelperMac() {
+}
+
+void SystemHotkeyHelperMac::LoadSystemHotkeys() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+
+  std::string library_path(base::mac::GetUserLibraryPath().value());
+  NSString* expanded_file_path =
+      [NSString stringWithFormat:@"%s%@",
+                                 library_path.c_str(),
+                                 kSystemHotkeyPlistExtension];
+
+  // Loads the file into memory.
+  NSData* data = [NSData dataWithContentsOfFile:expanded_file_path];
+  // Intentionally create the object with +1 retain count, as FileDidLoad
+  // will destroy the object.
+  NSDictionary* dictionary = [SystemHotkeyMap::DictionaryFromData(data) retain];
+
+  BrowserThread::PostTask(BrowserThread::UI,
+                          FROM_HERE,
+                          base::Bind(&SystemHotkeyHelperMac::FileDidLoad,
+                                     base::Unretained(this),
+                                     dictionary));
+}
+
+void SystemHotkeyHelperMac::FileDidLoad(NSDictionary* dictionary) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  bool success = map()->ParseDictionary(dictionary);
+  UMA_HISTOGRAM_BOOLEAN("OSX.SystemHotkeyMap.LoadSuccess", success);
+  [dictionary release];
+}
+
+}  // namespace content
diff --git a/content/browser/cocoa/system_hotkey_map.h b/content/browser/cocoa/system_hotkey_map.h
new file mode 100644
index 0000000..1909aa5
--- /dev/null
+++ b/content/browser/cocoa/system_hotkey_map.h
@@ -0,0 +1,66 @@
+// 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.
+
+#ifndef CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_MAP_H_
+#define CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_MAP_H_
+
+#import <Cocoa/Cocoa.h>
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+struct SystemHotkey;
+
+// Maintains a listing of all OSX system hotkeys. e.g. (cmd + `) These hotkeys
+// should have higher priority than web content, so NSEvents that correspond to
+// a system hotkey should not be passed to the renderer.
+class CONTENT_EXPORT SystemHotkeyMap {
+ public:
+  SystemHotkeyMap();
+  ~SystemHotkeyMap();
+
+  // Converts the plist stored in |data| into an NSDictionary. Returns nil on
+  // error.
+  static NSDictionary* DictionaryFromData(NSData* data);
+
+  // Parses the property list data commonly stored at
+  // ~/Library/Preferences/com.apple.symbolichotkeys.plist
+  // Returns false on encountering an irrecoverable error.
+  // Can be called multiple times. Only the results from the most recent
+  // invocation are stored.
+  bool ParseDictionary(NSDictionary* dictionary);
+
+  // Whether the event corresponds to a hotkey that has been reserved by the
+  // system.
+  bool IsEventReserved(NSEvent* event) const;
+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(SystemHotkeyMapTest, Parse);
+  FRIEND_TEST_ALL_PREFIXES(SystemHotkeyMapTest, ParseCustomEntries);
+  FRIEND_TEST_ALL_PREFIXES(SystemHotkeyMapTest, ParseMouse);
+
+  // Whether the hotkey has been reserved by the user.
+  bool IsHotkeyReserved(unsigned short key_code, NSUInteger modifiers) const;
+
+  // Create at least one record of a hotkey that is reserved by the user.
+  // Certain system hotkeys automatically reserve multiple key combinations.
+  void ReserveHotkey(unsigned short key_code,
+                     NSUInteger modifiers,
+                     NSString* system_effect);
+
+  // Create a record of a hotkey that is reserved by the user.
+  void ReserveHotkey(unsigned short key_code, NSUInteger modifiers);
+
+  std::vector<SystemHotkey> system_hotkeys_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemHotkeyMap);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_MAP_H_
diff --git a/content/browser/cocoa/system_hotkey_map.mm b/content/browser/cocoa/system_hotkey_map.mm
new file mode 100644
index 0000000..da04fa8
--- /dev/null
+++ b/content/browser/cocoa/system_hotkey_map.mm
@@ -0,0 +1,165 @@
+// 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.
+
+#import "content/browser/cocoa/system_hotkey_map.h"
+
+#pragma mark - NSDictionary Helper Functions
+
+namespace {
+
+// All 4 following functions return nil if the object doesn't exist, or isn't of
+// the right class.
+id ObjectForKey(NSDictionary* dict, NSString* key, Class aClass) {
+  id object = [dict objectForKey:key];
+  if (![object isKindOfClass:aClass])
+    return nil;
+  return object;
+}
+
+NSDictionary* DictionaryForKey(NSDictionary* dict, NSString* key) {
+  return ObjectForKey(dict, key, [NSDictionary class]);
+}
+
+NSArray* ArrayForKey(NSDictionary* dict, NSString* key) {
+  return ObjectForKey(dict, key, [NSArray class]);
+}
+
+NSNumber* NumberForKey(NSDictionary* dict, NSString* key) {
+  return ObjectForKey(dict, key, [NSNumber class]);
+}
+
+NSString* StringForKey(NSDictionary* dict, NSString* key) {
+  return ObjectForKey(dict, key, [NSString class]);
+}
+
+}  // namespace
+
+#pragma mark - SystemHotkey
+
+namespace content {
+
+struct SystemHotkey {
+  unsigned short key_code;
+  NSUInteger modifiers;
+};
+
+#pragma mark - SystemHotkeyMap
+
+SystemHotkeyMap::SystemHotkeyMap() {
+}
+SystemHotkeyMap::~SystemHotkeyMap() {
+}
+
+NSDictionary* SystemHotkeyMap::DictionaryFromData(NSData* data) {
+  if (!data)
+    return nil;
+
+  NSError* error = nil;
+  NSPropertyListFormat format;
+  NSDictionary* dictionary =
+      [NSPropertyListSerialization propertyListWithData:data
+                                                options:0
+                                                 format:&format
+                                                  error:&error];
+
+  if (![dictionary isKindOfClass:[NSDictionary class]])
+    return nil;
+
+  return dictionary;
+}
+
+bool SystemHotkeyMap::ParseDictionary(NSDictionary* dictionary) {
+  system_hotkeys_.clear();
+
+  if (!dictionary)
+    return false;
+
+  NSDictionary* hotkey_dictionaries =
+      DictionaryForKey(dictionary, @"AppleSymbolicHotKeys");
+  if (!hotkey_dictionaries)
+    return false;
+
+  for (NSString* hotkey_system_effect in [hotkey_dictionaries allKeys]) {
+    if (![hotkey_system_effect isKindOfClass:[NSString class]])
+      continue;
+
+    NSDictionary* hotkey_dictionary =
+        [hotkey_dictionaries objectForKey:hotkey_system_effect];
+    if (![hotkey_dictionary isKindOfClass:[NSDictionary class]])
+      continue;
+
+    NSNumber* enabled = NumberForKey(hotkey_dictionary, @"enabled");
+    if (!enabled || enabled.boolValue == NO)
+      continue;
+
+    NSDictionary* value = DictionaryForKey(hotkey_dictionary, @"value");
+    if (!value)
+      continue;
+
+    NSString* type = StringForKey(value, @"type");
+    if (!type || ![type isEqualToString:@"standard"])
+      continue;
+
+    NSArray* parameters = ArrayForKey(value, @"parameters");
+    if (!parameters || [parameters count] != 3)
+      continue;
+
+    NSNumber* key_code = [parameters objectAtIndex:1];
+    if (![key_code isKindOfClass:[NSNumber class]])
+      continue;
+
+    NSNumber* modifiers = [parameters objectAtIndex:2];
+    if (![modifiers isKindOfClass:[NSNumber class]])
+      continue;
+
+    ReserveHotkey(key_code.unsignedShortValue,
+                  modifiers.unsignedIntegerValue,
+                  hotkey_system_effect);
+  }
+
+  return true;
+}
+
+bool SystemHotkeyMap::IsEventReserved(NSEvent* event) const {
+  return IsHotkeyReserved(event.keyCode, event.modifierFlags);
+}
+
+bool SystemHotkeyMap::IsHotkeyReserved(unsigned short key_code,
+                                       NSUInteger modifiers) const {
+  modifiers &= NSDeviceIndependentModifierFlagsMask;
+  std::vector<SystemHotkey>::const_iterator it;
+  for (it = system_hotkeys_.begin(); it != system_hotkeys_.end(); ++it) {
+    if (it->key_code == key_code && it->modifiers == modifiers)
+      return true;
+  }
+  return false;
+}
+
+void SystemHotkeyMap::ReserveHotkey(unsigned short key_code,
+                                    NSUInteger modifiers,
+                                    NSString* system_effect) {
+  ReserveHotkey(key_code, modifiers);
+
+  // If a hotkey exists for toggling through the windows of an application, then
+  // adding shift to that hotkey toggles through the windows backwards.
+  if ([system_effect isEqualToString:@"27"])
+    ReserveHotkey(key_code, modifiers | NSShiftKeyMask);
+}
+
+void SystemHotkeyMap::ReserveHotkey(unsigned short key_code,
+                                    NSUInteger modifiers) {
+  // Hotkeys require at least one of control, command, or alternate keys to be
+  // down.
+  NSUInteger required_modifiers =
+      NSControlKeyMask | NSCommandKeyMask | NSAlternateKeyMask;
+  if ((modifiers & required_modifiers) == 0)
+    return;
+
+  SystemHotkey hotkey;
+  hotkey.key_code = key_code;
+  hotkey.modifiers = modifiers;
+  system_hotkeys_.push_back(hotkey);
+}
+
+}  // namespace content
diff --git a/content/browser/cocoa/system_hotkey_map_unittest.mm b/content/browser/cocoa/system_hotkey_map_unittest.mm
new file mode 100644
index 0000000..5f088fb
--- /dev/null
+++ b/content/browser/cocoa/system_hotkey_map_unittest.mm
@@ -0,0 +1,196 @@
+// 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 <gtest/gtest.h>
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+
+#include "base/files/file_path.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/path_service.h"
+#import "content/browser/cocoa/system_hotkey_map.h"
+#include "content/public/common/content_paths.h"
+
+namespace content {
+
+class SystemHotkeyMapTest : public ::testing::Test {
+ protected:
+  SystemHotkeyMapTest() {}
+
+  NSData* DataFromTestFile(const char* file) {
+    base::FilePath test_data_dir;
+    bool result = PathService::Get(DIR_TEST_DATA, &test_data_dir);
+    if (!result)
+      return nil;
+
+    base::FilePath test_path = test_data_dir.AppendASCII(file);
+    std::string test_path_string = test_path.AsUTF8Unsafe();
+    NSString* file_path =
+        [NSString stringWithUTF8String:test_path_string.c_str()];
+    return [NSData dataWithContentsOfFile:file_path];
+  }
+
+  void AddEntryToDictionary(BOOL enabled,
+                            unsigned short key_code,
+                            NSUInteger modifiers) {
+    NSMutableArray* parameters = [NSMutableArray array];
+    // The first parameter is unused.
+    [parameters addObject:[NSNumber numberWithInt:65535]];
+    [parameters addObject:[NSNumber numberWithUnsignedShort:key_code]];
+    [parameters addObject:[NSNumber numberWithUnsignedInteger:modifiers]];
+
+    NSMutableDictionary* value_dictionary = [NSMutableDictionary dictionary];
+    [value_dictionary setObject:parameters forKey:@"parameters"];
+    [value_dictionary setObject:@"standard" forKey:@"type"];
+
+    NSMutableDictionary* outer_dictionary = [NSMutableDictionary dictionary];
+    [outer_dictionary setObject:value_dictionary forKey:@"value"];
+
+    NSNumber* enabled_number = [NSNumber numberWithBool:enabled];
+    [outer_dictionary setObject:enabled_number forKey:@"enabled"];
+
+    NSString* key = [NSString stringWithFormat:@"%d", count_];
+    [system_hotkey_inner_dictionary_ setObject:outer_dictionary forKey:key];
+    ++count_;
+  }
+
+  virtual void SetUp() OVERRIDE {
+    system_hotkey_dictionary_.reset([[NSMutableDictionary alloc] init]);
+    system_hotkey_inner_dictionary_.reset([[NSMutableDictionary alloc] init]);
+    [system_hotkey_dictionary_ setObject:system_hotkey_inner_dictionary_
+                                  forKey:@"AppleSymbolicHotKeys"];
+    count_ = 100;
+  }
+
+  virtual void TearDown() OVERRIDE {
+    system_hotkey_dictionary_.reset();
+    system_hotkey_inner_dictionary_.reset();
+  }
+
+  // A constructed dictionary that matches the format of the one that would be
+  // parsed from the system hotkeys plist.
+  base::scoped_nsobject<NSMutableDictionary> system_hotkey_dictionary_;
+
+ private:
+  // A reference to the mutable dictionary to which new entries are added.
+  base::scoped_nsobject<NSMutableDictionary> system_hotkey_inner_dictionary_;
+  // Each entry in the system_hotkey_inner_dictionary_ needs to have a unique
+  // key. This count is used to generate those unique keys.
+  int count_;
+};
+
+TEST_F(SystemHotkeyMapTest, Parse) {
+  // This plist was pulled from a real machine. It is extensively populated,
+  // and has no missing or incomplete entries.
+  NSData* data = DataFromTestFile("mac/mac_system_hotkeys.plist");
+  ASSERT_TRUE(data);
+
+  NSDictionary* dictionary = SystemHotkeyMap::DictionaryFromData(data);
+  ASSERT_TRUE(dictionary);
+
+  SystemHotkeyMap map;
+  bool result = map.ParseDictionary(dictionary);
+  EXPECT_TRUE(result);
+
+  // Command + ` is a common key binding. It should exist.
+  unsigned short key_code = kVK_ANSI_Grave;
+  NSUInteger modifiers = NSCommandKeyMask;
+  EXPECT_TRUE(map.IsHotkeyReserved(key_code, modifiers));
+
+  // Command + Shift + ` is a common key binding. It should exist.
+  modifiers = NSCommandKeyMask | NSShiftKeyMask;
+  EXPECT_TRUE(map.IsHotkeyReserved(key_code, modifiers));
+
+  // Command + Shift + Ctr + ` is not a common key binding.
+  modifiers = NSCommandKeyMask | NSShiftKeyMask | NSControlKeyMask;
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, modifiers));
+
+  // Command + L is not a common key binding.
+  key_code = kVK_ANSI_L;
+  modifiers = NSCommandKeyMask;
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, modifiers));
+}
+
+TEST_F(SystemHotkeyMapTest, ParseNil) {
+  NSDictionary* dictionary = nil;
+
+  SystemHotkeyMap map;
+  bool result = map.ParseDictionary(dictionary);
+  EXPECT_FALSE(result);
+}
+
+TEST_F(SystemHotkeyMapTest, ParseMouse) {
+  // This plist was pulled from a real machine. It has missing entries,
+  // incomplete entries, and mouse hotkeys.
+  NSData* data = DataFromTestFile("mac/mac_system_hotkeys_sparse.plist");
+  ASSERT_TRUE(data);
+
+  NSDictionary* dictionary = SystemHotkeyMap::DictionaryFromData(data);
+  ASSERT_TRUE(dictionary);
+
+  SystemHotkeyMap map;
+  bool result = map.ParseDictionary(dictionary);
+  EXPECT_TRUE(result);
+
+  // Command + ` is a common key binding. It is missing.
+  // TODO(erikchen): OSX uses the default value when the keybinding is missing,
+  // so the hotkey should still be reserved.
+  // http://crbug.com/383558
+  unsigned short key_code = kVK_ANSI_Grave;
+  NSUInteger modifiers = NSCommandKeyMask;
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, modifiers));
+
+  // There is a mouse keybinding for 0x08. It should not apply to keyboard
+  // hotkeys.
+  key_code = kVK_ANSI_C;
+  modifiers = 0;
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, modifiers));
+
+  // Command + Alt + = is an accessibility shortcut. Its entry in the plist is
+  // incomplete.
+  // TODO(erikchen): OSX uses the default bindings, so this hotkey should still
+  // be reserved.
+  // http://crbug.com/383558
+  key_code = kVK_ANSI_Equal;
+  modifiers = NSCommandKeyMask | NSAlternateKeyMask;
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, modifiers));
+}
+
+TEST_F(SystemHotkeyMapTest, ParseCustomEntries) {
+  unsigned short key_code = kVK_ANSI_C;
+
+  AddEntryToDictionary(YES, key_code, 0);
+  AddEntryToDictionary(YES, key_code, NSAlphaShiftKeyMask);
+  AddEntryToDictionary(YES, key_code, NSShiftKeyMask);
+  AddEntryToDictionary(YES, key_code, NSControlKeyMask);
+  AddEntryToDictionary(YES, key_code, NSFunctionKeyMask);
+  AddEntryToDictionary(YES, key_code, NSFunctionKeyMask | NSControlKeyMask);
+  AddEntryToDictionary(NO, key_code, NSAlternateKeyMask);
+
+  SystemHotkeyMap map;
+
+  bool result = map.ParseDictionary(system_hotkey_dictionary_.get());
+  EXPECT_TRUE(result);
+
+  // Entries without control, command, or alternate key mask should not be
+  // reserved.
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, 0));
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, NSAlphaShiftKeyMask));
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, NSShiftKeyMask));
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, NSFunctionKeyMask));
+
+  // Unlisted entries should not be reserved.
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, NSCommandKeyMask));
+
+  // Disabled entries should not be reserved.
+  EXPECT_FALSE(map.IsHotkeyReserved(key_code, NSAlternateKeyMask));
+
+  // Other entries should be reserved.
+  EXPECT_TRUE(map.IsHotkeyReserved(key_code, NSControlKeyMask));
+  EXPECT_TRUE(
+      map.IsHotkeyReserved(key_code, NSFunctionKeyMask | NSControlKeyMask));
+}
+
+}  // namespace content
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index b26950a..e60324a 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -28,6 +28,8 @@
 #include "base/sys_info.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 #include "content/browser/accessibility/browser_accessibility_manager_mac.h"
+#import "content/browser/cocoa/system_hotkey_helper_mac.h"
+#import "content/browser/cocoa/system_hotkey_map.h"
 #include "content/browser/compositor/resize_lock.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
@@ -96,6 +98,17 @@ using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
 using blink::WebGestureEvent;
 
+namespace {
+
+// Whether a keyboard event has been reserved by OSX.
+BOOL EventIsReservedBySystem(NSEvent* event) {
+  content::SystemHotkeyHelperMac* helper =
+      content::SystemHotkeyHelperMac::GetInstance();
+  return helper->map()->IsEventReserved(event);
+}
+
+}  // namespace
+
 // These are not documented, so use only after checking -respondsToSelector:.
 @interface NSApplication (UndocumentedSpeechMethods)
 - (void)speakString:(NSString*)string;
@@ -2556,6 +2569,10 @@ void RenderWidgetHostViewMac::OnDisplayMetricsChanged(
   if ([[self window] firstResponder] != self)
     return NO;
 
+  // If the event is reserved by the system, then do not pass it to web content.
+  if (EventIsReservedBySystem(theEvent))
+    return NO;
+
   // If we return |NO| from this function, cocoa will send the key event to
   // the menu and only if the menu does not process the event to |keyDown:|. We
   // want to send the event to a renderer _before_ sending it to the menu, so
@@ -2603,6 +2620,19 @@ void RenderWidgetHostViewMac::OnDisplayMetricsChanged(
 
 - (void)keyEvent:(NSEvent*)theEvent wasKeyEquivalent:(BOOL)equiv {
   TRACE_EVENT0("browser", "RenderWidgetHostViewCocoa::keyEvent");
+
+  // If the user changes the system hotkey mapping after Chrome has been
+  // launched, then it is possible that a formerly reserved system hotkey is no
+  // longer reserved. The hotkey would have skipped the renderer, but would
+  // also have not been handled by the system. If this is the case, immediately
+  // return.
+  // TODO(erikchen): SystemHotkeyHelperMac should use the File System Events
+  // api to monitor changes to system hotkeys. This logic will have to be
+  // updated.
+  // http://crbug.com/383558.
+  if (EventIsReservedBySystem(theEvent))
+    return;
+
   DCHECK([theEvent type] != NSKeyDown ||
          !equiv == !([theEvent modifierFlags] & NSCommandKeyMask));
 
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 8adb26e..bc7356d 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -412,6 +412,10 @@
       'browser/child_process_launcher.h',
       'browser/child_process_security_policy_impl.cc',
       'browser/child_process_security_policy_impl.h',
+      'browser/cocoa/system_hotkey_helper_mac.h',
+      'browser/cocoa/system_hotkey_helper_mac.mm',
+      'browser/cocoa/system_hotkey_map.h',
+      'browser/cocoa/system_hotkey_map.mm',
       'browser/cross_site_request_manager.cc',
       'browser/cross_site_request_manager.h',
       'browser/devtools/devtools_agent_host_impl.cc',
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index 61f541c..5aa4712 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -407,6 +407,7 @@
         'browser/browser_url_handler_impl_unittest.cc',
         'browser/byte_stream_unittest.cc',
         'browser/child_process_security_policy_unittest.cc',
+        'browser/cocoa/system_hotkey_map_unittest.mm',
         'browser/compositor/software_browser_compositor_output_surface_unittest.cc',
         'browser/compositor/software_output_device_ozone_unittest.cc',
         'browser/databases_table_unittest.cc',
diff --git a/content/test/data/mac/mac_system_hotkeys.plist b/content/test/data/mac/mac_system_hotkeys.plist
new file mode 100644
index 0000000..c541463
--- /dev/null
+++ b/content/test/data/mac/mac_system_hotkeys.plist
@@ -0,0 +1,866 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>AppleSymbolicHotKeys</key>
+	<dict>
+		<key>10</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>96</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>11</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>97</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>118</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>18</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>119</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>19</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>12</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>122</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>120</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>20</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>121</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>21</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>13</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>98</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>15</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>56</integer>
+					<integer>28</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>16</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>160</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>65535</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>162</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>96</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>163</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>65535</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>17</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>61</integer>
+					<integer>24</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>175</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>65535</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>18</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>19</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>45</integer>
+					<integer>27</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>20</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>21</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>56</integer>
+					<integer>28</integer>
+					<integer>1835008</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>22</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>23</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>92</integer>
+					<integer>42</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>24</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>25</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>46</integer>
+					<integer>47</integer>
+					<integer>1835008</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>26</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>44</integer>
+					<integer>43</integer>
+					<integer>1835008</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>27</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>96</integer>
+					<integer>50</integer>
+					<integer>1048576</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>28</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>51</integer>
+					<integer>20</integer>
+					<integer>1179648</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>29</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>51</integer>
+					<integer>20</integer>
+					<integer>1441792</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>30</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>52</integer>
+					<integer>21</integer>
+					<integer>1179648</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>31</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>52</integer>
+					<integer>21</integer>
+					<integer>1441792</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>32</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>126</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>33</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>125</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>34</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>126</integer>
+					<integer>393216</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>35</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>125</integer>
+					<integer>393216</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>36</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>103</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>37</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>103</integer>
+					<integer>131072</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>51</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>39</integer>
+					<integer>50</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>52</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>100</integer>
+					<integer>2</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>53</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>107</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>54</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>113</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>55</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>107</integer>
+					<integer>524288</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>56</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>113</integer>
+					<integer>524288</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>57</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>100</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>59</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>96</integer>
+					<integer>1048576</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>60</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>32</integer>
+					<integer>49</integer>
+					<integer>1048576</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>61</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>32</integer>
+					<integer>49</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>62</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>111</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>63</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>111</integer>
+					<integer>131072</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>64</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>49</integer>
+					<integer>1048576</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>65</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>49</integer>
+					<integer>1572864</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>7</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>120</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>79</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>123</integer>
+					<integer>3932160</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>8</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>99</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>80</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>123</integer>
+					<integer>4063232</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>81</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>124</integer>
+					<integer>3932160</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>82</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>124</integer>
+					<integer>4063232</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>9</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>65535</integer>
+					<integer>118</integer>
+					<integer>262144</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+		<key>98</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>47</integer>
+					<integer>44</integer>
+					<integer>1179648</integer>
+				</array>
+				<key>type</key>
+				<string>standard</string>
+			</dict>
+		</dict>
+	</dict>
+</dict>
+</plist>
diff --git a/content/test/data/mac/mac_system_hotkeys_sparse.plist b/content/test/data/mac/mac_system_hotkeys_sparse.plist
new file mode 100644
index 0000000..ffda3af
--- /dev/null
+++ b/content/test/data/mac/mac_system_hotkeys_sparse.plist
@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>AppleSymbolicHotKeys</key>
+	<dict>
+		<key>15</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+		</dict>
+		<key>16</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>17</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+		</dict>
+		<key>18</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>19</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+		</dict>
+		<key>20</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>21</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>22</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>23</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+		</dict>
+		<key>24</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>25</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>26</key>
+		<dict>
+			<key>enabled</key>
+			<false/>
+		</dict>
+		<key>38</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>8</integer>
+					<integer>8</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>button</string>
+			</dict>
+		</dict>
+		<key>39</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>16</integer>
+					<integer>16</integer>
+					<integer>0</integer>
+				</array>
+				<key>type</key>
+				<string>button</string>
+			</dict>
+		</dict>
+		<key>40</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>8</integer>
+					<integer>8</integer>
+					<integer>131072</integer>
+				</array>
+				<key>type</key>
+				<string>button</string>
+			</dict>
+		</dict>
+		<key>41</key>
+		<dict>
+			<key>enabled</key>
+			<true/>
+			<key>value</key>
+			<dict>
+				<key>parameters</key>
+				<array>
+					<integer>16</integer>
+					<integer>16</integer>
+					<integer>131072</integer>
+				</array>
+				<key>type</key>
+				<string>button</string>
+			</dict>
+		</dict>
+	</dict>
+</dict>
+</plist>