Make stream captures work on canvases that are not in the DOM.

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
index bff9199f8ef1b879b5122f0d673e71e12f80e858..f79132363ff47760445530bdeff078f0df9acd8a 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -1389,15 +1389,12 @@ void WebGLRenderingContextBase::markContextChanged(
 
   LayoutBox* layoutBox = canvas()->layoutBox();
   if (layoutBox && layoutBox->hasAcceleratedCompositing()) {
-    m_markedCanvasDirty = true;
-    canvas()->clearCopiedImage();

[xlai (Olivia), 2017/02/08 17:58:40]

Why is this removed?

[Justin Novosad, 2017/02/08 18:43:12]

Because it was already being called by HTMLCanvasElement::didDraw

     layoutBox->contentChanged(changeType);
-  } else {
-    if (!m_markedCanvasDirty) {
-      m_markedCanvasDirty = true;
-      canvas()->didDraw(
-          FloatRect(FloatPoint(0, 0), FloatSize(clampedCanvasSize())));
-    }
+  }
+  if (!m_markedCanvasDirty) {
+    m_markedCanvasDirty = true;
+    IntSize canvasSize = clampedCanvasSize();
+    didDraw(SkIRect::MakeXYWH(0, 0, canvasSize.width(), canvasSize.height()));
   }
 }