Remove non-impl-side painting as an option for blink.

content/browser/gpu/compositor_util.h

Index: content/browser/gpu/compositor_util.h
diff --git a/content/browser/gpu/compositor_util.h b/content/browser/gpu/compositor_util.h
index 1475e6bc956a6ae4d32ab3b237602e641c0fa909..fab9099621b98e63c43ac5f95aeec3d0522db70c 100644
--- a/content/browser/gpu/compositor_util.h
+++ b/content/browser/gpu/compositor_util.h
@@ -20,10 +20,6 @@ CONTENT_EXPORT bool IsPropertyTreeVerificationEnabled();
 // Returns true if delegated-renderer is on (via flags, or platform default).
 CONTENT_EXPORT bool IsDelegatedRendererEnabled();
 
-// Returns true if impl-side painting is on (via flags, or platform default)
-// for the renderer.
-CONTENT_EXPORT bool IsImplSidePaintingEnabled();
-
 // Returns true if one-copy uploads is on (via flags, or platform default).
 // Only one of one-copy and zero-copy can be enabled at a time.
 CONTENT_EXPORT bool IsOneCopyUploadEnabled();