Media Controls: invalidate volume slider when value changes.

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

Index: third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
index 9cfad2953dc9454d0d0f1224e3319614bd5c7667..b5a95e3f43509d32fd5744917377a56a92e13d7c 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
@@ -856,8 +856,12 @@ bool MediaControlVolumeSliderElement::willRespondToMouseClickEvents() {
 }
 
 void MediaControlVolumeSliderElement::setVolume(double volume) {
-  if (value().toDouble() != volume)
-    setValue(String::number(volume));
+  if (value().toDouble() == volume)

[whywhat, 2017/01/09 16:06:59]

nit: is it okay to compare doubles like this? I remember that doing something
like abs(a - b) < epsilon is better in general - do we have a method for that in
WTF or base and does it matter? (e.g. if the volume values are always within 0-1
range with 0.1 intervals, it shouldn't)

[mlamouri (slow - plz ping), 2017/01/10 14:13:19]

In general, we can assume that any change is meaningful. There might be an
epsilon we could use but we could easily end up with issues such as many epsilon
changes leading to a large change we have been ignoring.

+    return;
+
+  setValue(String::number(volume));
+  if (LayoutObject* layoutObject = this->layoutObject())
+    layoutObject->setShouldDoFullPaintInvalidation();
 }
 
 bool MediaControlVolumeSliderElement::keepEventInNode(Event* event) {