[Mac] Add Home button to Default Touch Bar

chrome/browser/ui/cocoa/browser_window_touch_bar.mm

Index: chrome/browser/ui/cocoa/browser_window_touch_bar.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_touch_bar.mm b/chrome/browser/ui/cocoa/browser_window_touch_bar.mm
index d812ab1ad0045f6dadfe83c946904de5f2abd9b3..4af7489079a53659a3c25f1b6686666392a2649d 100644
--- a/chrome/browser/ui/cocoa/browser_window_touch_bar.mm
+++ b/chrome/browser/ui/cocoa/browser_window_touch_bar.mm
@@ -4,6 +4,8 @@
 
 #import "chrome/browser/ui/cocoa/browser_window_touch_bar.h"
 
+#include <memory>
+
 #include "base/mac/mac_util.h"
 #import "base/mac/scoped_nsobject.h"
 #import "base/mac/sdk_forward_declarations.h"
@@ -11,12 +13,16 @@
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/app/vector_icons/vector_icons.h"
 #include "chrome/browser/command_updater.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_command_controller.h"
+#import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #include "chrome/common/chrome_features.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/omnibox/browser/vector_icons.h"
+#include "components/prefs/pref_member.h"
 #include "components/search_engines/util.h"
 #include "components/toolbar/vector_icons.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -37,6 +43,7 @@ const NSTouchBarCustomizationIdentifier kBrowserWindowTouchBarId =
 // Touch bar items identifiers.
 const NSTouchBarItemIdentifier kBackForwardTouchId = @"BackForwardTouchId";
 const NSTouchBarItemIdentifier kReloadOrStopTouchId = @"ReloadOrStopTouchId";
+const NSTouchBarItemIdentifier kHomeTouchId = @"HomeTouchId";
 const NSTouchBarItemIdentifier kSearchTouchId = @"SearchTouchId";
 const NSTouchBarItemIdentifier kStarTouchId = @"StarTouchId";
 const NSTouchBarItemIdentifier kNewTabTouchId = @"NewTabTouchId";
@@ -53,7 +60,8 @@ const SkColor kTouchBarStarActiveColor = gfx::kGoogleBlue500;
 const int kTouchBarIconSize = 16;
 
 // The width of the search button in the touch bar.
-const int kTouchBarSearchButtonWidth = 280;
+const int kSearchBtnWidthWithHomeBtn = 205;
+const int kSearchBtnWidthWithoutHomeBtn = 280;
 
 // Creates an NSImage from the given VectorIcon.
 NSImage* CreateNSImageFromIcon(const gfx::VectorIcon& icon,
@@ -76,6 +84,23 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
   return button;
 }
 
+// A class registered for C++ notifications. This is used to detect changes in
+// the home button preferences and update the Touch Bar.
+class HomePrefNotificationBridge {
+ public:
+  explicit HomePrefNotificationBridge(BrowserWindowController* bwc)
+      : bwc_(bwc) {}
+
+  ~HomePrefNotificationBridge() {}
+
+  void UpdateTouchBar() { [bwc_ refreshTouchBar]; }

[Robert Sesek, 2017/03/10 17:39:56]

I don't understand why refreshTouchBar needs to exist? Can't
BrowserWindowTouchBar just update itself?

[spqchan, 2017/03/10 18:04:27]

In order to update the touch bar, the first responder containing the touchBar
property needs to be set nil.
It could be done in BrowserWindowTouchBar, but we probably want to update it
more often in the future so rather than having a lot of [GetWindow()
setTouchBar:nil] all over the code in the future, I thought it might be better
to just have one method that would refresh it.

[Robert Sesek, 2017/03/10 21:23:58]

You're right, that's what the docs say to do. That's a bit surprising to me, but
OK.

[spqchan, 2017/03/10 22:50:12]

I was surprised too when I found out. It's weird

+
+ private:
+  BrowserWindowController* bwc_;  // Weak.
+
+  DISALLOW_COPY_AND_ASSIGN(HomePrefNotificationBridge);
+};
+
 }  // namespace
 
 @interface BrowserWindowTouchBar () {
@@ -84,6 +109,14 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
 
   // The browser associated with the touch bar.
   Browser* browser_;  // Weak.
+
+  BrowserWindowController* bwc_;  // Weak, own us.
+
+  // Used to monitor the optional home button pref.
+  BooleanPrefMember showHomeButton_;
+
+  // Used to receive and handle notifications for the home button pref.
+  std::unique_ptr<HomePrefNotificationBridge> notificationBridge_;
 }
 
 // Creates and return the back and forward segmented buttons.
@@ -98,11 +131,20 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
 @synthesize isPageLoading = isPageLoading_;
 @synthesize isStarred = isStarred_;
 
-- (instancetype)initWithBrowser:(Browser*)browser {
+- (instancetype)initWithBrowser:(Browser*)browser
+        browserWindowController:(BrowserWindowController*)bwc {
   if ((self = [self init])) {
     DCHECK(browser);
     commandUpdater_ = browser->command_controller()->command_updater();
     browser_ = browser;
+    bwc_ = bwc;
+
+    notificationBridge_.reset(new HomePrefNotificationBridge(bwc_));
+    PrefService* prefs = browser->profile()->GetPrefs();
+    showHomeButton_.Init(
+        prefs::kShowHomeButton, prefs,
+        base::Bind(&HomePrefNotificationBridge::UpdateTouchBar,
+                   base::Unretained(notificationBridge_.get())));
   }
 
   return self;
@@ -114,10 +156,19 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
 
   base::scoped_nsobject<NSTouchBar> touchBar(
       [[NSClassFromString(@"NSTouchBar") alloc] init]);
-  NSArray* touchBarItemIdentifiers = @[
-    kBackForwardTouchId, kReloadOrStopTouchId, kSearchTouchId, kStarTouchId,
-    kNewTabTouchId
-  ];
+  NSArray* touchBarItemIdentifiers;
+  if (showHomeButton_.GetValue()) {
+    touchBarItemIdentifiers = @[
+      kBackForwardTouchId, kReloadOrStopTouchId, kHomeTouchId, kSearchTouchId,
+      kStarTouchId, kNewTabTouchId
+    ];
+  } else {
+    touchBarItemIdentifiers = @[
+      kBackForwardTouchId, kReloadOrStopTouchId, kSearchTouchId, kStarTouchId,
+      kNewTabTouchId
+    ];
+  }
+
   [touchBar setCustomizationIdentifier:kBrowserWindowTouchBarId];
   [touchBar setDefaultItemIdentifiers:touchBarItemIdentifiers];
   [touchBar setCustomizationAllowedItemIdentifiers:touchBarItemIdentifiers];
@@ -140,6 +191,9 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
         isPageLoading_ ? kNavigateStopIcon : kNavigateReloadIcon;
     int command_id = isPageLoading_ ? IDC_STOP : IDC_RELOAD;
     [touchBarItem setView:CreateTouchBarButton(icon, self, command_id)];
+  } else if ([identifier isEqualTo:kHomeTouchId]) {
+    [touchBarItem
+        setView:CreateTouchBarButton(kNavigateHomeIcon, self, IDC_HOME)];
   } else if ([identifier isEqualTo:kNewTabTouchId]) {
     [touchBarItem setView:CreateTouchBarButton(kNewTabMacTouchbarIcon, self,
                                                IDC_NEW_TAB)];
@@ -207,9 +261,9 @@ NSButton* CreateTouchBarButton(const gfx::VectorIcon& icon,
                          action:@selector(executeCommand:)];
   searchButton.imageHugsTitle = YES;
   searchButton.tag = IDC_FOCUS_LOCATION;
-  [searchButton.widthAnchor
-      constraintEqualToConstant:kTouchBarSearchButtonWidth]
-      .active = YES;
+  int width = showHomeButton_.GetValue() ? kSearchBtnWidthWithHomeBtn
+                                         : kSearchBtnWidthWithoutHomeBtn;
+  [searchButton.widthAnchor constraintEqualToConstant:width].active = YES;
   return searchButton;
 }