Insist on a Blink GC on RenderViewImpl unit test teardowns.

content/renderer/render_view_browsertest.cc

 // Copyright (c) 2012 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 <stddef.h>
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
@@ skipping 41 matching lines @@
 #include "content/test/test_render_frame.h"
 #include "net/base/net_errors.h"
 #include "net/cert/cert_status_flags.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebData.h"
 #include "third_party/WebKit/public/platform/WebHTTPBody.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #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"
 #include "third_party/WebKit/public/web/WebPerformance.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "third_party/WebKit/public/web/WebWindowFeatures.h"
 #include "ui/events/event.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/gfx/codec/jpeg_codec.h"
 #include "ui/gfx/range/range.h"
 
 #if defined(USE_AURA) && defined(USE_X11)
 #include <X11/Xlib.h>
 #include "ui/events/event_constants.h"
 #include "ui/events/keycodes/keyboard_code_conversion.h"
 #include "ui/events/test/events_test_utils.h"
 #include "ui/events/test/events_test_utils_x11.h"
 #endif
 
 #if defined(USE_OZONE)
 #include "ui/events/keycodes/keyboard_code_conversion.h"
 #endif
 
 #include "url/url_constants.h"
 
 using blink::WebFrame;
+using blink::WebHeap;
 using blink::WebInputEvent;
 using blink::WebLocalFrame;
 using blink::WebMouseEvent;
 using blink::WebRuntimeFeatures;
 using blink::WebString;
 using blink::WebTextDirection;
 using blink::WebURLError;
 
 namespace content {
 
@@ skipping 64 matching lines @@
   ~RenderViewImplTest() override {}
 
   void SetUp() override {
     // Enable Blink's experimental and test only features so that test code
     // does not have to bother enabling each feature.
     WebRuntimeFeatures::enableExperimentalFeatures(true);
     WebRuntimeFeatures::enableTestOnlyFeatures(true);
     RenderViewTest::SetUp();
   }
 
+  // To avoid flaky leak reports, insist on GCing
+  // Blink upon shutdown to clear out garbage.
+  void TearDown() override {
+    WebHeap::collectGarbageForTesting();

[haraken, 2016/01/24 09:27:56]

collectAllGarbageForTesting would be better.

[sof, 2016/01/24 12:35:18]

That's what I thought would be tidier too, but forcing a (conservative) GC is
vital here (and sufficient for these tests.)

*AllGarbageForTesting()'s posting of tasks to run precise GCs along with
processing pending messages afterwards isn't a strong enough guarantee -- you
can still observe flaky leak reports when doing that.

So I will keep it like this.

+    RenderViewTest::TearDown();
+  }
+
   RenderViewImpl* view() {
     return static_cast<RenderViewImpl*>(view_);
   }
 
   int view_page_id() {
     return view()->page_id_;
   }
 
   TestRenderFrame* frame() {
     return static_cast<TestRenderFrame*>(view()->GetMainRenderFrame());
@@ skipping 310 matching lines @@
   ExecuteJavaScriptForTests(
       "document.getElementById('elt_text').value = 'foo';");
   ProcessPendingMessages();
   if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
     EXPECT_TRUE(render_thread_->sink().GetUniqueMessageMatching(
         FrameHostMsg_UpdateState::ID));
   } else {
     EXPECT_TRUE(render_thread_->sink().GetUniqueMessageMatching(
         ViewHostMsg_UpdateState::ID));
   }
-  ProcessPendingMessages();
 }
 
 TEST_F(RenderViewImplTest, OnNavigationHttpPost) {
   // An http url will trigger a resource load so cannot be used here.
   CommonNavigationParams common_params;
   StartNavigationParams start_params;
   RequestNavigationParams request_params;
   common_params.url = GURL("data:text/html,<div>Page</div>");
   common_params.navigation_type = FrameMsg_Navigate_Type::NORMAL;
   common_params.transition = ui::PAGE_TRANSITION_TYPED;
@@ skipping 2219 matching lines @@
       FROM_HERE,
       base::Bind(&DevToolsAgentTest::CloseWhilePaused, base::Unretained(this)));
   ExecuteJavaScriptForTests("debugger;");
 
   // CloseWhilePaused should resume execution and continue here.
   EXPECT_FALSE(IsPaused());
   Detach();
 }
 
 }  // namespace content