Updated hover media feature to comply updated media queries spec

The spec (http://dev.w3.org/csswg/mediaqueries-4/#hover)  for the hover
media query has added keywords for the feature's value. This CL updates
the media query keywords to propertly parse and evaluate the feature;
however, it remains only sparsely implemented. The hover (and pointer)
media queries currently only produce non-false output for touchscreen
devices. The plumbing work to actually produce the correct results in
all cases will be done in a future CL.

BUG=136119

Review URL: https://codereview.chromium.org/451113002

git-svn-id: svn://svn.chromium.org/blink/trunk@180006 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/fast/media/mq-pointer-expected.txt

@@ -9,8 +9,9 @@ Query "(pointer:coARse)": false
 Query "(pointer:bogusvalue)": false
 Query "(pointer:fine)": false
 Query "(hover)": false
-Query "(hover:0)": false
-Query "(hover:1)": false
+Query "(hover:none)": false
+Query "(hover:hover)": false
+Query "(hover:on-demand)": false
 Query "(hover:bogusvalue)": false
 ------------- with touch screen -------------
 Query "(pointer)": true
@@ -20,8 +21,9 @@ Query "(pointer:coarse)": true
 Query "(pointer:coARse)": true
 Query "(pointer:bogusvalue)": false
 Query "(pointer:fine)": false
-Query "(hover)": false
-Query "(hover:0)": true
-Query "(hover:1)": false
+Query "(hover)": true
+Query "(hover:none)": false
+Query "(hover:hover)": false
+Query "(hover:on-demand)": true
 Query "(hover:bogusvalue)": false
 

third_party/WebKit/LayoutTests/fast/media/mq-pointer.html

@@ -23,8 +23,9 @@
             "(pointer:bogusvalue)",
             "(pointer:fine)",
             "(hover)",
-            "(hover:0)",
-            "(hover:1)",
+            "(hover:none)",
+            "(hover:hover)",
+            "(hover:on-demand)",
             "(hover:bogusvalue)" ];
         for (var index=0; index < queries.length; index++) {
             log("Query &quot;" + queries[index] + "&quot: " +

third_party/WebKit/Source/core/css/CSSValueKeywords.in

@@ -891,6 +891,11 @@ alphabetic
 coarse
 fine
 
+// (hover:) media feature
+//  none
+on-demand
+hover
+
 // blend modes
 // normal
 multiply

third_party/WebKit/Source/core/css/MediaQueryEvaluator.cpp

@@ -53,6 +53,7 @@
 #include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "platform/PlatformScreen.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/geometry/FloatRect.h"
 #include "wtf/HashMap.h"
 
@@ -527,15 +528,28 @@ static bool hoverMediaFeatureEval(const MediaQueryExpValue& value, MediaFeatureP
     if (pointer == MediaValues::UnknownPointer)
         return false;
 
-    float number = 1;
-    if (value.isValid()) {
-        if (!numberValue(value, number))
+    // FIXME: Remove the old code once we're sure this doesn't break anything significant.
+    if (RuntimeEnabledFeatures::hoverMediaQueryKeywordsEnabled()) {
+        if (!value.isValid())
+            return pointer != MediaValues::NoPointer;
+
+        if (!value.isID)
             return false;
-    }
 
-    return (pointer == MediaValues::NoPointer && !number)
-        || (pointer == MediaValues::TouchPointer && !number)
-        || (pointer == MediaValues::MousePointer && number == 1);
+        return (pointer == MediaValues::NoPointer && value.id == CSSValueNone)
+            || (pointer == MediaValues::TouchPointer && value.id == CSSValueOnDemand)
+            || (pointer == MediaValues::MousePointer && value.id == CSSValueHover);
+    } else {
+        float number = 1;
+        if (value.isValid()) {
+            if (!numberValue(value, number))
+                return false;
+        }
+
+        return (pointer == MediaValues::NoPointer && !number)
+            || (pointer == MediaValues::TouchPointer && !number)
+            || (pointer == MediaValues::MousePointer && number == 1);
+    }
 }
 
 static bool pointerMediaFeatureEval(const MediaQueryExpValue& value, MediaFeaturePrefix, const MediaValues& mediaValues)

third_party/WebKit/Source/core/css/MediaQueryEvaluatorTest.cpp

@@ -44,8 +44,9 @@ TestCase screenTestCases[] = {
     {"tv and (scan: progressive)", 0},
     {"(pointer: coarse)", 0},
     {"(pointer: fine)", 1},
-    {"(hover: 1)", 1},
-    {"(hover: 0)", 0},
+    {"(hover: hover)", 1},
+    {"(hover: on-demand)", 0},
+    {"(hover: none)", 0},
     {0, 0} // Do not remove the terminator line.
 };
 

third_party/WebKit/Source/core/css/MediaQueryExp.cpp

@@ -35,6 +35,7 @@
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "platform/Decimal.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/text/StringBuffer.h"
 #include "wtf/text/StringBuilder.h"
 
@@ -49,6 +50,7 @@ static inline bool featureWithCSSValueID(const String& mediaFeature, const CSSPa
 
     return mediaFeature == orientationMediaFeature
         || mediaFeature == pointerMediaFeature
+        || (mediaFeature == hoverMediaFeature && RuntimeEnabledFeatures::hoverMediaQueryKeywordsEnabled())
         || mediaFeature == scanMediaFeature;
 }
 
@@ -60,6 +62,9 @@ static inline bool featureWithValidIdent(const String& mediaFeature, CSSValueID
     if (mediaFeature == pointerMediaFeature)
         return ident == CSSValueNone || ident == CSSValueCoarse || ident == CSSValueFine;
 
+    if (mediaFeature == hoverMediaFeature && RuntimeEnabledFeatures::hoverMediaQueryKeywordsEnabled())
+        return ident == CSSValueNone || ident == CSSValueOnDemand || ident == CSSValueHover;
+
     if (mediaFeature == scanMediaFeature)
         return ident == CSSValueInterlace || ident == CSSValueProgressive;
 
@@ -148,7 +153,7 @@ static inline bool featureWithZeroOrOne(const String& mediaFeature, const CSSPar
         return false;
 
     return mediaFeature == gridMediaFeature
-        || mediaFeature == hoverMediaFeature;
+        || (mediaFeature == hoverMediaFeature && !RuntimeEnabledFeatures::hoverMediaQueryKeywordsEnabled());
 }
 
 static inline bool featureWithAspectRatio(const String& mediaFeature)

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in

@@ -141,6 +141,9 @@ TargetedStyleRecalc status=stable
 // touchscreen) in ApplyWebPreferences.
 Touch status=stable
 
+// Temporary setting to allow easy rollback of change to hover media feature.
+HoverMediaQueryKeywords status=stable
+
 TouchIconLoading
 ThreadedParserDataReceiver status=experimental
 UserSelectAll status=experimental