LayoutTheme: Invalidate cache on WebThemeEngine change.

A LayoutThemeDefault instance can be associated to a real
WebThemeEngine or a mock WebThemeEngine, which have different
metrics. We need to invalidate a cached value when a WebThemeEngine is
switched.

The bug affects only layout tests.

BUG=673754

Review-Url: https://codereview.chromium.org/2627773002
Cr-Commit-Position: refs/heads/master@{#442799}

third_party/WebKit/LayoutTests/TestExpectations

@@ -758,6 +758,8 @@ crbug.com/498539 [ Win7 ] inspector/elements/styles-4/styles-update-from-js.html
 crbug.com/596968 [ Win ] inspector-protocol/input/eventTimestamp.html [ Failure Pass ]
 
 crbug.com/487281 [ Mac ] fast/forms/select/menulist-narrow-width.html [ Failure ]
+crbug.com/673754 fast/forms/color/input-appearance-color.html [ NeedsRebaseline ]
+crbug.com/673754 fast/forms/select/menulist-appearance-basic.html [ NeedsRebaseline ]
 
 crbug.com/543110 [ Mac ] fast/text/international/text-shaping-arabic.html [ Failure ]
 

third_party/WebKit/Source/core/layout/LayoutTheme.h

@@ -58,6 +58,10 @@ class CORE_EXPORT LayoutTheme : public RefCounted<LayoutTheme> {
 
   virtual ThemePainter& painter() = 0;
 
+  // This function is called after associated WebThemeEngine instance
+  // was replaced. This is called only in tests.
+  virtual void didChangeThemeEngine() {}
+
   static void setSizeIfAuto(ComputedStyle&, const IntSize&);
 
   // This method is called whenever style has been computed for an element and

third_party/WebKit/Source/core/layout/LayoutThemeDefault.cpp

@@ -363,6 +363,10 @@ float LayoutThemeDefault::clampedMenuListArrowPaddingSize(
   return originalSize * style.effectiveZoom();
 }
 
+void LayoutThemeDefault::didChangeThemeEngine() {
+  m_menuListArrowWidthInDIP = 0;
+}
+
 // static
 void LayoutThemeDefault::setDefaultFontSize(int fontSize) {
   LayoutThemeFontProvider::setDefaultFontSize(fontSize);

third_party/WebKit/Source/core/layout/LayoutThemeDefault.h

@@ -147,6 +147,7 @@ class CORE_EXPORT LayoutThemeDefault : public LayoutTheme {
 
  private:
   ThemePainter& painter() override { return m_painter; }
+  void didChangeThemeEngine() override;
 
   int menuListInternalPadding(const ComputedStyle&, int padding) const;
 

third_party/WebKit/Source/web/WebKit.cpp

@@ -35,6 +35,7 @@
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8Initializer.h"
 #include "core/animation/AnimationClock.h"
+#include "core/layout/LayoutTheme.h"
 #include "core/page/Page.h"
 #include "core/workers/WorkerBackingThread.h"
 #include "gin/public/v8_platform.h"
@@ -124,6 +125,7 @@ bool layoutTestMode() {
 
 void setMockThemeEnabledForTest(bool value) {
   LayoutTestSupport::setMockThemeEnabledForTest(value);
+  LayoutTheme::theme().didChangeThemeEngine();
 }
 
 void setFontAntialiasingEnabledForTest(bool value) {