RenderViewTest: really drain the event loop before shutting down Blink.

And with that in place, undo the partial fix by r371169.

R=haraken,jochen
BUG=581948
NOTRY=true

Review URL: https://codereview.chromium.org/1645923002

Cr-Commit-Position: refs/heads/master@{#372088}

content/public/test/render_view_test.cc

@@ -409,6 +409,8 @@ void RenderViewTest::TearDown() {
 
   leak_detector->collectGarbageAndReport();
 
+  base::RunLoop().RunUntilIdle();
+
   blink_platform_impl_.Shutdown();
   blink::shutdown();
 

content/renderer/render_view_browsertest.cc

@@ -59,7 +59,6 @@
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
 #include "third_party/WebKit/public/web/WebDataSource.h"
 #include "third_party/WebKit/public/web/WebDeviceEmulationParams.h"
-#include "third_party/WebKit/public/web/WebHeap.h"
 #include "third_party/WebKit/public/web/WebHistoryCommitType.h"
 #include "third_party/WebKit/public/web/WebHistoryItem.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
@@ -88,7 +87,6 @@
 #include "url/url_constants.h"
 
 using blink::WebFrame;
-using blink::WebHeap;
 using blink::WebInputEvent;
 using blink::WebLocalFrame;
 using blink::WebMouseEvent;
@@ -173,13 +171,6 @@ class RenderViewImplTest : public RenderViewTest {
     RenderViewTest::SetUp();
   }
 
-  // To avoid flaky leak reports, insist on GCing
-  // Blink upon shutdown to clear out garbage.
-  void TearDown() override {
-    WebHeap::collectGarbageForTesting();
-    RenderViewTest::TearDown();
-  }
-
   RenderViewImpl* view() {
     return static_cast<RenderViewImpl*>(view_);
   }