Don't build the task manager into Android builds.

chrome/browser/prefs/browser_prefs.cc

 // Copyright (c) 2012 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 "chrome/browser/prefs/browser_prefs.h"
 
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/autofill/autofill_manager.h"
 #include "chrome/browser/background/background_mode_manager.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
@@ skipping 106 matching lines @@
   IntranetRedirectDetector::RegisterPrefs(local_state);
   KeywordEditorController::RegisterPrefs(local_state);
   ManagedMode::RegisterPrefs(local_state);
   MetricsLog::RegisterPrefs(local_state);
   MetricsService::RegisterPrefs(local_state);
   NotificationUIManager::RegisterPrefs(local_state);
   PrefProxyConfigTrackerImpl::RegisterPrefs(local_state);
   ProfileInfoCache::RegisterPrefs(local_state);
   ProfileManager::RegisterPrefs(local_state);
   SSLConfigServiceManager::RegisterPrefs(local_state);
-  TaskManager::RegisterPrefs(local_state);
   UpgradeDetector::RegisterPrefs(local_state);
   WebCacheManager::RegisterPrefs(local_state);
 
+#if defined(ENABLE_TASK_MANAGER)
+  TaskManager::RegisterPrefs(local_state);
+#endif
+
 #if defined(ENABLE_CONFIGURATION_POLICY)
   policy::CloudPolicySubsystem::RegisterPrefs(local_state);
 #endif
 
 #if defined(ENABLE_SAFE_BROWSING)
   SafeBrowsingService::RegisterPrefs(local_state);
 #endif
 
 #if defined(TOOLKIT_VIEWS)
   BrowserView::RegisterBrowserViewPrefs(local_state);
@@ skipping 119 matching lines @@
       user_prefs->Set(prefs::kBrowserWindowPlacement, *(pref->GetValue()));
     }
     local_state->ClearPref(prefs::kBrowserWindowPlacement);
 
     local_state->SetInteger(prefs::kMultipleProfilePrefMigration,
                             current_version | WINDOWS_PREFS);
   }
 }
 
 }  // namespace browser