Fix WeakPtrFactory member ordering in chrome/browser

Changing in the intialization order of WeakPtrFactory such that all
member variables should appear before the WeakPtrFactory to ensure
that any WeakPtrs to Controller are invalidated before its members
variable's destructors are executed, rendering them invalid.

BUG=303818

Review URL: https://codereview.chromium.org/557833006

Cr-Commit-Position: refs/heads/master@{#296216}
6 files changed