diff --git a/dom/canvas/WebGL2ContextDraw.cpp b/dom/canvas/WebGL2ContextDraw.cpp
index 517f3f06fb23..c930f8b0848c 100644
--- a/dom/canvas/WebGL2ContextDraw.cpp
+++ b/dom/canvas/WebGL2ContextDraw.cpp
@@ -13,7 +13,7 @@ namespace mozilla {
 void
 WebGL2Context::DrawRangeElements(GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type, GLintptr offset)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("drawRangeElements: Not Implemented.");
 }
 
 } // namespace mozilla
diff --git a/dom/canvas/WebGL2ContextFramebuffers.cpp b/dom/canvas/WebGL2ContextFramebuffers.cpp
index 47356b4a96b6..5fb2605ae2c3 100644
--- a/dom/canvas/WebGL2ContextFramebuffers.cpp
+++ b/dom/canvas/WebGL2ContextFramebuffers.cpp
@@ -333,13 +333,13 @@ WebGL2Context::BlitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY
 void
 WebGL2Context::FramebufferTextureLayer(GLenum target, GLenum attachment, GLuint texture, GLint level, GLint layer)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("framebufferTextureLayer: Not Implemented.");
 }
 
 void
 WebGL2Context::GetInternalformatParameter(JSContext*, GLenum target, GLenum internalformat, GLenum pname, JS::MutableHandleValue retval)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("getInternalformatParameter: Not Implemented.");
 }
 
 // Map attachments intended for the default buffer, to attachments for a non-
diff --git a/dom/canvas/WebGL2ContextTextures.cpp b/dom/canvas/WebGL2ContextTextures.cpp
index 33938666ad58..9992f134eeb0 100644
--- a/dom/canvas/WebGL2ContextTextures.cpp
+++ b/dom/canvas/WebGL2ContextTextures.cpp
@@ -431,7 +431,7 @@ WebGL2Context::TexSubImage3D(GLenum target, GLint level,
                              GLenum format, GLenum type, dom::ImageData* data,
                              ErrorResult& rv)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("texSubImage3D: Not implemented.");
 }
 
 void
@@ -439,7 +439,7 @@ WebGL2Context::CopyTexSubImage3D(GLenum target, GLint level,
                                  GLint xoffset, GLint yoffset, GLint zoffset,
                                  GLint x, GLint y, GLsizei width, GLsizei height)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("copyTexSubImage3D: Not implemented.");
 }
 
 void
@@ -447,7 +447,7 @@ WebGL2Context::CompressedTexImage3D(GLenum target, GLint level, GLenum internalf
                                     GLsizei width, GLsizei height, GLsizei depth,
                                     GLint border, GLsizei imageSize, const dom::ArrayBufferView& data)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("compressedTexImage3D: Not implemented.");
 }
 
 void
@@ -455,7 +455,7 @@ WebGL2Context::CompressedTexSubImage3D(GLenum target, GLint level, GLint xoffset
                                        GLsizei width, GLsizei height, GLsizei depth,
                                        GLenum format, GLsizei imageSize, const dom::ArrayBufferView& data)
 {
-    MOZ_CRASH("Not Implemented.");
+    GenerateWarning("compressedTexSubImage3D: Not implemented.");
 }
 
 JS::Value