Remove "from all browsers" memory details mode

chrome/browser/site_details_browsertest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/site_details.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 40 matching lines @@
 
 namespace {
 
 class TestMemoryDetails : public MetricsMemoryDetails {
  public:
   TestMemoryDetails()
       : MetricsMemoryDetails(base::Bind(&base::DoNothing), nullptr) {}
 
   void StartFetchAndWait() {
     uma_.reset(new base::HistogramTester());
-    StartFetch(FROM_CHROME_ONLY);
+    StartFetch();
     content::RunMessageLoop();
   }
 
   // Returns a HistogramTester which observed the most recent call to
   // StartFetchAndWait().
   base::HistogramTester* uma() { return uma_.get(); }
 
   int GetOutOfProcessIframeCount() {
     std::vector<Bucket> buckets =
         uma_->GetAllSamples("SiteIsolation.OutOfProcessIframes");
@@ skipping 1158 matching lines @@
   content::NavigateIframeToURL(
       tab, "child-1", extension2->GetResourceURL("/blank_iframe.html"));
   details = new TestMemoryDetails();
   details->StartFetchAndWait();
   EXPECT_THAT(details->uma()->GetAllSamples(
                   "SiteIsolation.SiteInstancesPerBrowsingInstance"),
               DependingOnPolicy(ElementsAre(Bucket(1, 2)),
                                 ElementsAre(Bucket(1, 1), Bucket(3, 1)),
                                 ElementsAre(Bucket(1, 1), Bucket(5, 1))));
 }