Destroy BookmarkBridge in ChromeActivity#onDestroy

Failing to do this leaves behind a native observer of bookmark events
that can hold onto a profile that subsequently gets deleted. When the
observer is triggered, accessing the deleted profile causes a crash.

Bug: 1092391
Change-Id: I7864d2c63ae4952aee64cb28574c0404cb868dd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2236092Reviewed-by: Filip Gorski <fgorski@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Patrick Noland <pnoland@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776489}

chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java

@@ -1255,6 +1255,12 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
             if (selector != null) selector.destroy();
         }
 
+        if (mBookmarkBridgeSupplier != null) {
+            BookmarkBridge bookmarkBridge = mBookmarkBridgeSupplier.get();
+            if (bookmarkBridge != null) bookmarkBridge.destroy();
+            mBookmarkBridgeSupplier = null;
+        }
+
         mActivityTabProvider.destroy();
 
         mComponent = null;