Encode frame number in pixel data for pose sync

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 4c2ebadfd568aebe2fd11d95476bb8508c0a495a..b5d874152cb5c5e821b0d81662282b5574d83b54 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -1136,7 +1136,11 @@ void WebGLRenderingContextBase::initializeNewContext() {
   m_vertexAttribType.resize(m_maxVertexAttribs);
 
   contextGL()->Viewport(0, 0, drawingBufferWidth(), drawingBufferHeight());
-  contextGL()->Scissor(0, 0, drawingBufferWidth(), drawingBufferHeight());
+  m_scissorBox[0] = m_scissorBox[1] = 0;
+  m_scissorBox[2] = drawingBufferWidth();
+  m_scissorBox[3] = drawingBufferHeight();
+  contextGL()->Scissor(m_scissorBox[0], m_scissorBox[1], m_scissorBox[2],
+                       m_scissorBox[3]);
 
   drawingBuffer()->contextProvider()->setLostContextCallback(
       convertToBaseCallback(WTF::bind(
@@ -1375,8 +1379,12 @@ void WebGLRenderingContextBase::restoreStateAfterClear() {
     return;
 
   // Restore the state that the context set.
-  if (m_scissorEnabled)
+  if (m_scissorEnabled) {
     contextGL()->Enable(GL_SCISSOR_TEST);
+    // WebVR's VRDisplay uses a custom scissor box, need to restore that too.
+    contextGL()->Scissor(m_scissorBox[0], m_scissorBox[1], m_scissorBox[2],
+                         m_scissorBox[3]);
+  }
   contextGL()->ClearColor(m_clearColor[0], m_clearColor[1], m_clearColor[2],
                           m_clearColor[3]);
   contextGL()->ColorMask(m_colorMask[0], m_colorMask[1], m_colorMask[2],
@@ -4156,6 +4164,10 @@ void WebGLRenderingContextBase::scissor(GLint x,
                                         GLsizei height) {
   if (isContextLost())
     return;
+  m_scissorBox[0] = x;
+  m_scissorBox[1] = y;
+  m_scissorBox[2] = width;
+  m_scissorBox[3] = height;
   contextGL()->Scissor(x, y, width, height);
 }