Update other unittests to use newly added TestingBrowserProcess::GetGlobal().

chrome/browser/background/background_mode_manager_unittest.cc

Index: chrome/browser/background/background_mode_manager_unittest.cc
diff --git a/chrome/browser/background/background_mode_manager_unittest.cc b/chrome/browser/background/background_mode_manager_unittest.cc
index 9acd91fdb1eccd870a0694091a6c25f62a15adda..b03339abaaa7f388bda699a508346e609736fe77 100644
--- a/chrome/browser/background/background_mode_manager_unittest.cc
+++ b/chrome/browser/background/background_mode_manager_unittest.cc
@@ -19,8 +19,7 @@
 class BackgroundModeManagerTest : public testing::Test {
  public:
   BackgroundModeManagerTest()
-      : profile_manager_(
-            static_cast<TestingBrowserProcess*>(g_browser_process)) {}
+      : profile_manager_(TestingBrowserProcess::GetGlobal()) {}
   ~BackgroundModeManagerTest() {}
   void SetUp() {
     command_line_.reset(new CommandLine(CommandLine::NO_PROGRAM));