Remove the command buffer method glGetImageivCHROMIUM.

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h

Index: third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h
diff --git a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h
index c6d86e4e7897291fa812573e9e04fc06a5227c81..70d792f32019918c34dbb1df7c641e01946b4dd0 100644
--- a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h
+++ b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h
@@ -260,11 +260,6 @@ private:
         GLuint textureId = 0;
         GLuint imageId = 0;
         bool immutable = false;
-
-        // A GpuMemoryBuffer is a concept that the compositor understands. and
-        // is able to operate on. The id is scoped to renderer process.
-        GLint gpuMemoryBufferId = -1;
-
         TextureParameters parameters;
     };