Android: Handle multiple ProfileDestroyers correctly

Multiple ProfileDestroyers destroying a single Profile is sorted out
in ProfileDestroyer::DestroyOffTheRecordProfileNow by the first
destroyer nulling out the pointer to the Profile in the others so they
won't destroy the same Profile again.

It has a bug breaking out the loop after handling the first one. The
right way is finding and nulling out all the Destroyers. This CL
fixes it.

Bug: 1029677
Change-Id: I7d8efe60a28613040e0a2afd9db0640ea3602c2d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2113391
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752594}

chrome/browser/profiles/profile_destroyer.cc

@@ -122,8 +122,7 @@ void ProfileDestroyer::DestroyOffTheRecordProfileNow(Profile* const profile) {
         // these potential leaks, but we handle it in release so that we don't
         // crash or corrupt profile data on disk.
         LOG(WARNING) << "A render process host wasn't destroyed early enough.";
-        (*i)->profile_ = NULL;
-        break;
+        (*i)->profile_ = nullptr;
       }
     }
   }
@@ -163,7 +162,7 @@ ProfileDestroyer::ProfileDestroyer(Profile* const profile, HostSet* hosts)
 ProfileDestroyer::~ProfileDestroyer() {
   if (profile_) {
     ProfileDestroyer::DestroyOffTheRecordProfileNow(profile_);
-    profile_ = nullptr;
+    DCHECK(!profile_);
   }
 
   // Once the profile is deleted, all renderer hosts must have been deleted.