Refactor frame navigation/detach state cleanup to be more sane.

Source/core/css/MediaQueryEvaluatorTest.cpp

 // Copyright 2014 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 "config.h"
 #include "core/css/MediaQueryEvaluator.h"
 
 #include "core/MediaTypeNames.h"
 #include "core/css/MediaList.h"
 #include "core/css/MediaValuesCached.h"
@@ skipping 134 matching lines @@
 
     MediaQueryEvaluator mediaQueryEvaluator(&pageHolder->frame());
     testMQEvaluator(viewportTestCases, mediaQueryEvaluator);
     pageHolder->frameView().setMediaType(MediaTypeNames::print);
     testMQEvaluator(printTestCases, mediaQueryEvaluator);
 }
 
 TEST(MediaQueryEvaluatorTest, DynamicNoView)
 {
     OwnPtr<DummyPageHolder> pageHolder = DummyPageHolder::create(IntSize(500, 500));
-    RefPtrWillBePersistent<FrameView> view = pageHolder->frame().view();
-    pageHolder->frame().setView(nullptr);
-    MediaQueryEvaluator mediaQueryEvaluator(&pageHolder->frame());
-    RefPtrWillBePersistent<MediaQuerySet> querySet = MediaQuerySet::create("foobar");
-    bool output = false;
-    ASSERT_EQ(output, mediaQueryEvaluator.eval(querySet.get()));
-    pageHolder->frame().setView(view);

[dcheng, 2015/04/03 14:35:45]

Since this test didn't need to flout the invariants about frame state, I
simplified it a bit. This meant I had to remove an ASSERT in DummyPageHolder's
dtor, but I think that's OK: holding references to keep objects alive to test
weird edge cases of frame detach is a legitimate need of unit test code, and
does not indicate a logic error.

+    RefPtrWillBeRawPtr<LocalFrame> frame = &pageHolder->frame();
+    pageHolder.clear();
+    ASSERT_EQ(nullptr, frame->view());
+    MediaQueryEvaluator mediaQueryEvaluator(frame.get());
+    RefPtrWillBeRawPtr<MediaQuerySet> querySet = MediaQuerySet::create("foobar");
+    EXPECT_EQ(false, mediaQueryEvaluator.eval(querySet.get()));
 }
 
 } // namespace