Clear MatchedPropertiesCache on StyleRule changes.

third_party/WebKit/Source/core/dom/StyleEngineTest.cpp

 // Copyright 2016 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 "core/dom/StyleEngine.h"
 
+#include "core/css/CSSRuleList.h"
+#include "core/css/CSSStyleRule.h"
+#include "core/css/CSSStyleSheet.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/css/parser/CSSParserContext.h"
 #include "core/dom/Document.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/dom/shadow/ShadowRootInit.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLStyleElement.h"
 #include "core/testing/DummyPageHolder.h"
 #include "platform/heap/Heap.h"
@@ skipping 349 matching lines @@
   document().view()->updateAllLifecyclePhases();
 
   unsigned afterCount = styleEngine().styleForElementCount();
   EXPECT_EQ(0u, afterCount - beforeCount);
 
   ASSERT_TRUE(t1->computedStyle());
   EXPECT_EQ(makeRGB(0, 128, 0),
             t1->computedStyle()->visitedDependentColor(CSSPropertyColor));
 }
 
+TEST_F(StyleEngineTest, ModifyStyleRuleMatchedPropertiesCache) {
+  // Test that the MatchedPropertiesCache is cleared when a StyleRule is
+  // modified. The MatchedPropertiesCache caches results based on
+  // StylePropertySet pointers. When a mutable StylePropertySet is modified,
+  // the pointer doesn't change, yet the declarations do.
+
+  document().body()->setInnerHTML(
+      "<style id='s1'>#t1 { color: blue }</style>"
+      "<div id='t1'>Green</div>");
+  document().view()->updateAllLifecyclePhases();
+
+  Element* t1 = document().getElementById("t1");
+  ASSERT_TRUE(t1);
+  ASSERT_TRUE(t1->computedStyle());
+  EXPECT_EQ(makeRGB(0, 0, 255),
+            t1->computedStyle()->visitedDependentColor(CSSPropertyColor));
+
+  CSSStyleSheet* sheet = toCSSStyleSheet(document().styleSheets().item(0));
+  ASSERT_TRUE(sheet);
+  ASSERT_TRUE(sheet->cssRules());
+  CSSStyleRule* styleRule = toCSSStyleRule(sheet->cssRules()->item(0));
+  ASSERT_TRUE(styleRule);
+  ASSERT_TRUE(styleRule->style());
+
+  // Modify the StylePropertySet once to make it a mutable set. Subsequent
+  // modifications will not change the StylePropertySet pointer and cache hash
+  // value will be the same.
+  styleRule->style()->setProperty("color", "red", "", ASSERT_NO_EXCEPTION);
+  document().view()->updateAllLifecyclePhases();
+
+  ASSERT_TRUE(t1->computedStyle());
+  EXPECT_EQ(makeRGB(255, 0, 0),
+            t1->computedStyle()->visitedDependentColor(CSSPropertyColor));
+
+  styleRule->style()->setProperty("color", "green", "", ASSERT_NO_EXCEPTION);
+  document().view()->updateAllLifecyclePhases();
+
+  ASSERT_TRUE(t1->computedStyle());
+  EXPECT_EQ(makeRGB(0, 128, 0),
+            t1->computedStyle()->visitedDependentColor(CSSPropertyColor));
+}
+
 }  // namespace blink