Make <meter> transparent if -webkit-appearance:none or background CSS property is specified.

third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp

Index: third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp b/third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp
index b6f78cc587bcd96da5b77ca94e36995b8dae0274..a5e6e7cb8b1d6ad8234a0d18ddb5bdd8e3ac18ef 100644
--- a/third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MeterShadowElement.cpp
@@ -42,6 +42,25 @@ namespace blink {
 
 using namespace HTMLNames;
 
+inline MeterFallbackElement::MeterFallbackElement(Document& document)
+    : HTMLDivElement(document)
+{
+    setHasCustomStyleCallbacks();
+}
+
+DEFINE_NODE_FACTORY(MeterFallbackElement)
+
+PassRefPtr<ComputedStyle> MeterFallbackElement::customStyleForLayoutObject()
+{
+    Element* host = shadowHost();
+    RefPtr<ComputedStyle> style = originalStyleForLayoutObject();
+    if (!host || !host->computedStyle() || host->computedStyle()->appearance() != MeterPart)
+        return style.release;
+    RefPtr<ComputedStyle> newStyle = ComputedStyle::clone(*style);
+    newStyle->setDisplay(NONE);
+    return newStyle.release();
+}
+
 inline MeterShadowElement::MeterShadowElement(Document& document)
     : HTMLDivElement(document)
 {
@@ -61,6 +80,7 @@ bool MeterShadowElement::layoutObjectIsNeeded(const ComputedStyle& style)
 inline MeterInnerElement::MeterInnerElement(Document& document)
     : MeterShadowElement(document)
 {
+    setHasCustomStyleCallbacks();
 }
 
 PassRefPtrWillBeRawPtr<MeterInnerElement> MeterInnerElement::create(Document& document)
@@ -84,6 +104,17 @@ LayoutObject* MeterInnerElement::createLayoutObject(const ComputedStyle&)
     return new LayoutMeter(this);
 }
 
+PassRefPtr<ComputedStyle> MeterInnerElement::customStyleForLayoutObject()
+{
+    Element* host = shadowHost();
+    RefPtr<ComputedStyle> style = originalStyleForLayoutObject();
+    if (!host || !host->computedStyle() || host->computedStyle()->appearance() == MeterPart)
+        return style.release;
+    RefPtr<ComputedStyle> newStyle = ComputedStyle::clone(*style);
+    newStyle->setDisplay(NONE);
+    return newStyle.release();
+}
+
 inline MeterBarElement::MeterBarElement(Document& document)
     : MeterShadowElement(document)
 {