Reland 1: "mac: Allow Chrome to hand off its active URL to other devices."

The original CL used instance variables in a class extension and automatic
generation of ivars for synthesized properties, features only available on
64-bit builds. The Mac Memory bots are still compiling Chromium in 32-bits.
This reland removes the usage of those features.

> This CL adds the class HandoffManager, which is responsible for interfacing
> with Apple's Handoff APIs. It takes a GURL, and exposes that GURL to Handoff.
>
> This CL adds the class ActiveWebContentsObserver, which is responsible for
> listening to changes to the active browser, the active tab, and the visible
> URL. It notifies its delegate when any of this state might have changed.
>
> AppControllerMac is the delegate of ActiveWebContentsObserver, as well as the
> owner of the HandoffManager. When it receives a delegate callback, it passes an
> updated GURL to the HandoffManager. There is some minimal logic in
> AppControllerMac that prevents URLs from incognito windows from being passed to
> the HandoffManager.
>
> BUG=431051, 438823
> Committed: https://crrev.com/708abc5b0abb5e0916d779bf6d1342fd472a2aa1
> Cr-Commit-Position: refs/heads/master@{#307846}

BUG=431051, 438823
TBR=sky, erikwright, mmenke, avi

Review URL: https://codereview.chromium.org/794853004

Cr-Commit-Position: refs/heads/master@{#308005}

1 files changed, 80 insertions, 2 deletions

diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 2e2dfe5..604f217 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -63,6 +63,7 @@
 #import "chrome/browser/ui/cocoa/confirm_quit.h"
 #import "chrome/browser/ui/cocoa/confirm_quit_panel_controller.h"
 #import "chrome/browser/ui/cocoa/encoding_menu_controller_delegate_mac.h"
+#include "chrome/browser/ui/cocoa/handoff_active_url_observer_bridge.h"
 #import "chrome/browser/ui/cocoa/history_menu_bridge.h"
 #include "chrome/browser/ui/cocoa/last_active_browser_cocoa.h"
 #import "chrome/browser/ui/cocoa/profiles/profile_menu_controller.h"
@@ -83,6 +84,7 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
+#include "components/handoff/handoff_manager.h"
 #include "components/handoff/handoff_utility.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/signin/core/common/profile_management_switches.h"
@@ -209,9 +211,10 @@ bool IsProfileSignedOut(Profile* profile) {
   return cache.ProfileIsSigninRequiredAtIndex(profile_index);
 }
 
-}  // anonymous namespace
+}  // namespace
+
+@interface AppController () <HandoffActiveURLObserverBridgeDelegate>
 
-@interface AppController (Private)
 - (void)initMenuState;
 - (void)initProfileMenu;
 - (void)updateConfirmToQuitPrefMenuItem:(NSMenuItem*)item;
@@ -240,6 +243,25 @@ bool IsProfileSignedOut(Profile* profile) {
 // this method is called, and that tab is the NTP, then this method closes the
 // NTP after all the |urls| have been opened.
 - (void)openUrlsReplacingNTP:(const std::vector<GURL>&)urls;
+
+// Whether instances of this class should use the Handoff feature.
+- (BOOL)shouldUseHandoff;
+
+// This method passes |handoffURL| to |handoffManager_|.
+- (void)passURLToHandoffManager:(const GURL&)handoffURL;
+
+// Lazily creates the Handoff Manager. Updates the state of the Handoff
+// Manager. This method is idempotent. This should be called:
+// - During initialization.
+// - When the current tab navigates to a new URL.
+// - When the active browser changes.
+// - When the active browser's active tab switches.
+// |webContents| should be the new, active WebContents.
+- (void)updateHandoffManager:(content::WebContents*)webContents;
+
+// Given |webContents|, extracts a GURL to be used for Handoff. This may return
+// the empty GURL.
+- (GURL)handoffURLFromWebContents:(content::WebContents*)webContents;
 @end
 
 class AppControllerProfileObserver : public ProfileInfoCacheObserver {
@@ -776,6 +798,12 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
 
   startupComplete_ = YES;
 
+  Browser* browser =
+      FindLastActiveWithHostDesktopType(chrome::HOST_DESKTOP_TYPE_NATIVE);
+  content::WebContents* activeWebContents = nullptr;
+  if (browser)
+    activeWebContents = browser->tab_strip_model()->GetActiveWebContents();
+  [self updateHandoffManager:activeWebContents];
   [self openStartupUrls];
 
   PrefService* localState = g_browser_process->local_state();
@@ -786,6 +814,9 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
         base::Bind(&chrome::BrowserCommandController::UpdateOpenFileState,
                    menuState_.get()));
   }
+
+  handoff_active_url_observer_bridge_.reset(
+      new HandoffActiveURLObserverBridge(self));
 }
 
 // This is called after profiles have been loaded and preferences registered.
@@ -1638,6 +1669,53 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
                                     error:(NSError*)error {
 }
 
+#pragma mark - Handoff Manager
+
+- (BOOL)shouldUseHandoff {
+  return base::mac::IsOSYosemiteOrLater();
+}
+
+- (void)passURLToHandoffManager:(const GURL&)handoffURL {
+  [handoffManager_ updateActiveURL:handoffURL];
+}
+
+- (void)updateHandoffManager:(content::WebContents*)webContents {
+  if (![self shouldUseHandoff])
+    return;
+
+  if (!handoffManager_)
+    handoffManager_.reset([[HandoffManager alloc] init]);
+
+  GURL handoffURL = [self handoffURLFromWebContents:webContents];
+  [self passURLToHandoffManager:handoffURL];
+}
+
+- (GURL)handoffURLFromWebContents:(content::WebContents*)webContents {
+  if (!webContents)
+    return GURL();
+
+  Profile* profile =
+      Profile::FromBrowserContext(webContents->GetBrowserContext());
+  if (!profile)
+    return GURL();
+
+  // Handoff is not allowed from an incognito profile. To err on the safe side,
+  // also disallow Handoff from a guest profile.
+  if (profile->GetProfileType() != Profile::REGULAR_PROFILE)
+    return GURL();
+
+  if (!webContents)
+    return GURL();
+
+  return webContents->GetVisibleURL();
+}
+
+#pragma mark - HandoffActiveURLObserverBridgeDelegate
+
+- (void)handoffActiveURLChanged:(content::WebContents*)webContents {
+  [self updateHandoffManager:webContents];
+}
+
 @end  // @implementation AppController
 
 //---------------------------------------------------------------------------