Don't create a LoFiBarPopupController if SnackbarManager is null

BUG=594381

Review URL: https://codereview.chromium.org/1803823002

Cr-Commit-Position: refs/heads/master@{#381078}
(cherry picked from commit e086724)

Review URL: https://codereview.chromium.org/1805093002 .

Cr-Commit-Position: refs/branch-heads/2661@{crosswalk-project#242}
Cr-Branched-From: ef6f6ae-refs/heads/master@{#378081}

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

@@ -565,8 +565,10 @@ public Tab(int id, int parentId, boolean incognito, Context context,
         mWindowAndroid = window;
         mLaunchType = type;
         if (mThemedApplicationContext != null) {
-            mLoFiBarPopupController = new LoFiBarPopupController(
-                    mThemedApplicationContext, getSnackbarManager());
+            if (getSnackbarManager() != null) {
+                mLoFiBarPopupController = new LoFiBarPopupController(
+                        mThemedApplicationContext, getSnackbarManager());
+            }
             Resources resources = mThemedApplicationContext.getResources();
             mIdealFaviconSize = resources.getDimensionPixelSize(R.dimen.default_favicon_size);
             mDefaultThemeColor = mIncognito