WebGL: Free temporary GPU resources held by inactive or hidden WebGL.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

Index: Source/core/html/canvas/CanvasRenderingContext2D.cpp
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.cpp b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
index 4d8569c799fa9e4ce795094724248f8c99e9b2a3..8946f49d9ed1203ca6c15e43c8e99e0489a2512c 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.cpp
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
@@ -2269,6 +2269,13 @@ int CanvasRenderingContext2D::getFontBaseline(const FontMetrics& fontMetrics) co
     return 0;
 }
 
+void CanvasRenderingContext2D::setIsHidden(bool hidden)
+{
+    ImageBuffer* buffer = canvas()->buffer();
+    if (buffer)
+        buffer->setIsHidden(hidden);
+}
+
 blink::WebLayer* CanvasRenderingContext2D::platformLayer() const
 {
     return canvas()->buffer() ? canvas()->buffer()->platformLayer() : 0;